Datasheet 74LV4799SN, 74LV4799SD, 74LV4799PW, 74LV4799N, 74LV4799D Datasheet (Philips)

...

Download

Page 1

 

74LV4799

Timer for NiCd and NiMH chargers

Product specification Supersedes data of 1998 Apr 07 IC24 Data Handbook

1998 Apr 20

INTEGRATED CIRCUITS

Page 2

Philips Semiconductors Product specification

74L V4799Timer for NiCd and NiMH chargers

1998 Apr 20 853-2058 19258

FEA TURES

•Wide supply voltage range of 0.9 V to 6 V allows 1 to 4-cell

applications

•10 V allowed on special inputs

•Supports virtually all battery chargers, including switched-mode

power supplies

•On-chip timer calculates the actual capacity of the battery by

measuring the charger time, discharge time and self-discharge time

•Automatic switch-over to trickle charge after completion of the

charge time

•Can be adjusted for use with different types of batteries:

– Charge time: 4 to 16 hours – Discharge time: 15 minutes to 4.7 hours – Self-discharge time: 50 to 100 days

•Battery status indication included:

– LED output for charging/full indication – MOLLI

output for battery-low indication

•LED mode select allows two different methods of indication

•Automatic power-ON reset

•Low-power consumption

•Requires only a few peripheral components

•Very accurate on-chip oscillator

•Scan test facilities included

•I

category: non-standard.

APPLICA TIONS

•Time-controlled NiCd and NiMH low-current chargers

•Domestic appliances such as rechargeable battery shavers,

electric toothbrushes etc.

•Portable equipment such as notebook PCs, laptop PCs, camera

flash units etc.

•Personal communications like cordless telephones, personal

mobile radios, pagers, etc.

DESCRIPTION

The 74LV4799 is a low-voltage Si-gate CMOS control IC for battery management. It consists of:

•17-stage divider

•10-stage up/down counter

•Control logic

•Integrated precision oscillator (using external timing components)

•Automatic power-ON reset

•Scan test facilities

•Battery charging/full indication output (LED)

•Battery-low indication output (MOLLI)

•Open-drain-N outputs for driving the load transistor

Battery management with the 74L V4799 is based on the principle of time measurement. It measures the charge time, discharge time and self-discharge time by means of a very accurate on-chip oscillator, a divider and an up/down counter.

PIN CONFIGURATION

SV01643

LED

PWRS

MOLLI

/SCO

SCI

SCAN

GND

DIS

SEL

OSC

QUICK REFERENCE DA TA

GND = 0V; T

amb

= 25°C

SYMBOL PARAMETER CONDITIONS TYPICAL TYPICAL TYPICAL UNIT

DC supply voltage 0.9 6.0 V

Operating supply current

VCC = 3.3V; self-discharge mode; R

= 100 k;

= 220nF

36 µA

f

Oscillator frequency tolerance VCC = 1 to 6 V 7 %

ORDERING INFORMATION

PACKAGES TEMPERATURE RANGE OUTSIDE NORTH AMERICA NORTH AMERICA CODE

16-Pin Plastic DIL 0°C to +70°C 74LV4799 N 74LV4799 N SOT38-4 16-Pin Plastic SO 0°C to +70°C 74LV4799 D 74LV4799 D SOT109-1 16-Pin Plastic SSOP Type II 0°C to +70°C 74LV4799 DB 74LV4799 DB SOT338-1 16-Pin Plastic TSSOP Type I 0°C to +70°C 74LV4799 PW 74LV4799PW DH SOT403-1

Page 3

Philips Semiconductors Product specification

74LV4799Timer for NiCd and NiMH chargers

1998 Apr 20

FUNCTIONAL DIAGRAM

SV01644

OSCILLATOR CP

GND

MOLLI/SCO

LED

EN EN

GND

OSC

SCI

SCAN

PWRS

DIS

SEL

3–STAGE DIVIDER

5–14 STAGE

DIVIDER

POWER–ON

RESET

CONTROL LOGIC

10–STAGE UP/DOWN COUNTER

10 11

GND

IEC LOGIC SYMBOL

SV01645

IOSC RS RD

DIS

SCI SCO

MOLLI

4 2 3

LED

U+[2]

U+[1]

SCAN/Z1

PWRS

SEL

CT=0

I=0

BATT. TIMER

13 12 11 10

9 15 14

Page 4

Philips Semiconductors Product specification

74LV4799Timer for NiCd and NiMH chargers

1998 Apr 20

PIN DESCRIPTION

PIN NO. SYMBOL NAME AND FUNCTION

1 LED LED driver output pin (active LOW) 2 EN Enable output (active HIGH) 3 EN Enable output (active LOW) 4 V

External power input 5 PWRS Power sense input 6 MOLLI/SCO More-or-less-low-indication output (active LOW)/scan test output 7 SEL LED mode select input 8 GND Ground (0 V) 9 DIS Discharge input (active LOW)

10 R

External resistor pin 3-State oscillator output (charge)

11 R

External resistor pin 3-State output (discharge)

12 R

External resistor pin 3-State output (self-discharge)

13 I

OSC

Oscillator input

14 SCAN Scan test mode select input (active HIGH) 15 SCI Scan test input 16 V

Positive supply voltage

Power On Reset.

An automatic Power On Reset initiates the IC when the battery is discharged and power is connected to the circuit. The initial condition is the charge mode in which the counter is reset and counts from zero up to maximum. At start up, the battery therefore always receives a full charge cycle. When a partially charged battery is inserted, it may be over-charged during the first cycle. To guard against this, simply replace the resistor at the R

pin with an NTC type which is in good thermal contact with the battery. If the temperature of the battery increases, the frequency of the oscillator also increases to quickly reach a counter full indication and switch-over to trickle charge. With a battery that is almost completely discharged, the POR input can also be activated during discharge or self-discharge. The counter will then be reset to zero. This is a correct action while returning to the initial condition.

Power-on sensing.

Because this IC supports virtually all battery chargers, the PWRS input has a broad input frequency spectrum (active HIGH to 100 kHz). A pull-down circuit at the PWRS input allows detection of the open state which corresponds to an inactive charger. A HIGH level on the PWRS input, or an AC signal up to 100 kHz, enables the charge mode.

Start-up with low battery voltage.

Good start-up, even with an un-charged battery, is assured by using the V

input. The voltage on the VIN input biases the external

bipolar transistors at the EN or EN

output, even if the IC is not yet functioning. After the battery has received sufficient charge, the internal control logic takes over control of the EN and EN outputs.

Charge mode.

This mode is selected when PWRS is active (HIGH or pulsed) and the discharge input DIS

is HIGH. The EN output is HIGH, and the

output is LOW initiating continuous charge of the battery. The counter then counts from the zero state up to the maximum value. The clock frequency is determined by the external capacitor and resistor connected to the R

output. The counter stops when it

reaches its maximum value and the EN and EN

outputs switch over

from the continuous charge to the trickle charge mode.

Trickle charge mode.

At the maximum counter value, it is assumed that the battery is fully charged. The counter stops and remains on this maximum value.

The EN and EN

outputs switch over from the continues charge to the trickle charge mode. In the trickle charge mode, the average charge current is reduced to only compensate the self-discharge of the battery by using the dedicated duty cycle control. The control is dedicated because it adjusts the duty cycle in inverse proportion to the load current, resulting in a fixed charger current irrespective of the kind of charger (e.g. 4-hour or 16-hour charger). In the trickle charge mode, the oscillator circuitry alternately generates 4 periods of R

-C1 time-constant, and 3 periods of the RS -C1 time-constant

(See Figure 1).

Discharge mode.

The discharge input (DIS

) is used to detect the discharge of the

battery. If DIS

is LOW, the counter counts down. The clock frequency is determined by the external capacitor and resistor at the RD output. If PWRS is inactive (LOW or open), the EN output is LOW, and the EN

output is in the high impedance OFF-state (no charge of the battery). This is called the discharge mode. If PWRS is active, the circuit is in the charge/discharge mode.

Charge/Discharge mode.

If DIS

is LOW and PWRS is active (HIGH or pulsed), the circuit is in the charge/discharge mode. The counter counts down. The clock frequency is determined by the external capacitor and resistor tied at the R

output. The EN output is HIGH, and the EN output is LOW initiating continuous charge of the battery. The battery is therefore charged and discharged at the same instant, thereby maintaining a better load condition of the battery.

Page 5

Philips Semiconductors Product specification

74LV4799Timer for NiCd and NiMH chargers

1998 Apr 20

Self-discharge mode.

If DIS

is HIGH and PWRS is inactive (LOW or open), the battery is being neither charged nor discharged. The circuit is in the self-discharge mode. This mode represents the battery leakage (self-discharge). The counter counts down. The clock frequency is determined by the external capacitor and resistor at the R

output.

When the counter reaches the zero state, it stops.

LED mode select.

The LED

output drives a battery status LED which indicates the charge/full status of the battery. For optimum flexibility, two modes of operation are built-in.

•Mode 1: If SEL is LOW, the LED output is active LOW in the

charge mode, and the LED blinks with a frequency of about 1 Hz during trickle charge.

•Mode 2: If SEL is HIGH or open, the LED output blinks with a

frequency of about 0.25 Hz in the charge mode, and is active LOW during trickle charge. In the discharge or self-discharge mode, the LED

output is open except when PWRS is active (HIGH or pulsed). Then, the battery is charging and discharging simultaneously. Although the discharge mode is dominant, the LED output is active when PWRS is also active.

NOTE: The blink frequency depends on the oscillator frequency.

(See application information)

Low indication.

As part of the user interface, the MOLL

I output shows when the

battery needs to be charged. MOLLI

stands for More Or Less Low Indication (active LOW). The function is as follows: In the discharge mode, (DIS

is active LOW), the counter counts down and, when it

reaches the zero state, it stops. If DIS

is switched HIGH, the MOLLI output gives an output signal of four periods of about one second, with a 50% duty cycle. This can be used to activate a buzzer. The MOLLI

output signal of four periods will be interrupted as soon as

PWRS is activated. Alarm indication.

If an almost completely discharged battery is connected to the charger, it may not be noticed by the user if the load switch is still

on. To prevent damaging the battery , an alarm signal on the LED output will alert the user to switch off the load. The alarm signal is easily recognized, because the LED

output will blink at a higher frequency than normal (about 5 Hz instead of 1 Hz). This alarm indication is only active if the SEL input is HIGH or open. If the SEL input is LOW, no alarm indication is present, because in many applications simultaneous charging and discharging is quite acceptable. (See charge/discharge mode)

Scan test mode.

If the SCAN input (pin 14) is made active HIGH, the circuit is in the test mode. The tester clock is connected to the I

OSC

pin (pin 13). In the scan mode, the on–chip oscillator is bypassed to allow rapid testing of the divider/counter. The scan test patterns are available on request. The scan test data is entered serially through the SCI input (pin 15). The scan out data is present on the MOLLI

/SCO output

(pin 6), which then acts as a scan output.

Remaining energy indication.

The scan test facility can be used as a remaining energy indication because the value of the counter can be read out at the scan output (MOLLI

/SCO). This is done by briefly interrupting the normal mode of operation, putting the circuit in the scan mode, and reading out the counter value. The circuit then reverts to the normal mode. This only works correctly with the MOLLI

/SCO output and SCI input linked (round coupled loop) and with exactly 49 clock pulses applied to the I

OSC

input.

The serial scan-out data is available on the MOLLI/SCO output. The value of the counter can be decoded by reading the correct bits. Details are given later in the section “Application information”.

Output drivers EN and EN

In one-cell battery (low-voltage) applications, the drive from the ENABLE output (EN

) is insufficient to provide the base current directly for the external bipolar PNP regulator transistor. The inverse signal has therefore been made available at the ENABLE output (EN) to drive an extra bipolar NPN transistor that can provide the base current for the bipolar PNP regulator transistor as shown in Figure 2.

FUNCTION TABLE 1

OPERATING

INPUTS OUTPUTS DIVIDER/COUNTER

OPERATING

MODES

PWRS V

DIS EN EN R

MODE VALUE

Charge

H or

H H H L Z Z Count up 22 sections < max

Trickle charge

H or

H H Z Stop max

Charge/discharge

H or

H L H L Z Z Count down 18 sections ≥ min Discharge L or open X L L Z Z Z Count down 18 sections ≥ min Self-discharge L or open X H L Z Z Z Count down 27 sections ≥ min

Page 6

Philips Semiconductors Product specification

74LV4799Timer for NiCd and NiMH chargers

1998 Apr 20

FUNCTION TABLE 2

STATUS

INPUTS OUTPUTS COUNTER

STATUS

INDICATION

PWRS DIS SEL

(1)

LED MOLLI MODE VALUE

H or

H L L Z Count up < max

arge

H or

H H or open Z Count up < max

Charge/discharge

H or

L L L Z Count down ≥ min

H or

H L

Stop max

Trickle charge

H or H H or open L

Stop max Discharge L or open L X Z Z Count down > min Self-discharge L or open H X Z Z Count down > min Low L or open ↑ X Z Stop min Low ↑ ↑ X Z Z

(2)

Count up ≥ min Alarm H or L H or open

Count down ≥ min

NOTES:

1. Don’t change SEL during operation.

2. The MOLLI

function will be interrupted as soon as PWRS is activated.

H = HIGH voltage level L = LOW voltage level Z = high impedance OFF-state X = don’t care

= pulsed (H/L) = pulsed (Z/L) = 4 periods of about one second (Z/L)

↑ = LOW-to-HIGH level transition

SV01646

Z–state

OSC

Operation in the trickle charge mode. The duration of the RC cycle determines the duty cycle of the enable outputs (EN and EN), allowing a dedicated control. The average trickle charge current will compensate for the self-discharge, independent of the charge current.

Figure 1. Trickle charge mode characteristics.

Page 7

Philips Semiconductors Product specification

74LV4799Timer for NiCd and NiMH chargers

1998 Apr 20

RECOMMENDED OPERATING CONDITIONS

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNIT

DC supply voltage See Note 1 0.9 1.2 6 V

Input voltage pins 4, 5, and 9 Input voltage pins 7, 13, 14, and 15

0 0

– –

Output voltage pins 10, 11, and 12 Output voltage pins 1, 2, 3, and 6

0 0

– –

amb

Operating ambient temperature range in free air

See DC and AC

characteristics per device

0 +70 °C

Input rise and fall times pin 5 – – 10 ms

tr, t

Input rise and fall times pins 7, 14 and 15

VCC = 1.0V; VI = 1.0V VCC = 2.0V; VI = 2.0V V

= 3.0V; VI = 4.5V

VCC = 3.6V; VI = 6.0V

– – – –

500 200 100

Input rise and fall times pin 9 – – 2 µs

NOTE:

1. Single sided input protection applied on pins 4, 5, and 9.

ABSOLUTE MAXIMUM RATINGS

2, 3

In accordance with the Absolute Maximum Rating System (IEC 134). Voltages are referenced to GND (ground = 0 V).

SYMBOL

PARAMETER CONDITIONS MIN MAX UNIT

DC supply voltage –0.5 +7.0 V DC input diode current pins 4, 5 and 9 V

< –0.5 or VI > 12 V ±20

DC input diode current pins 7, 13, 14 and 15 V

< –0.5 or VI > VCC + 0.5 V +20

NON repetitive peak DC input diode current pin 9

> 10 V and t < 10 s; see note 1

DC input voltage range pins 4, 5 and 9 –0.5 +12 V

DC input voltage range pins 7, 13, 14 and 15 –0.5 VCC + 0.5 V

DC output diode current pins 1, 2, 3 and 6 VO < –0.5 V –20 mA

DC output sink current pins 1, 2, 3 and 6 VO > 0 V –25 mA

DC output diode current pins 10, 11 and 12 VO < –0.5 or V

> VCC + 0.5 V ±20 mA

DC output sink or source current pins 10, 11 and 12 –0.5 V < VO < VCC + 0.5 V ±25 mA

GND

, I

DC GND or VCC current ±50 mA

stg

Storage temperature range –65 +150 °C Power dissipation per package for temperature range: –40 to +125 °C

Power dissi ation er ackage

Plastic DIL

for tem erature range: 40 to +125 C

above + 70 °C derate linearly with 12 mW/K 750

tot

Plastic mini-pack (SO)

above + 70 °C derate linearly with 8 mW/K

500

astic shrink mini-pack

(SSOP

and

TSSOP)

above + 60 °C derate linearly with 5.5 m

W/K

400

NOTES:

1. In applications where a motor is present, the input voltage may exceed the maximum V

, level of 10 V at the DIS input for a very short period

when the motor is switched off.

2. Stresses beyond those listed may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those under “recommended operating conditions” is not implied. Exposure to absolute maximum rated conditions for extended periods may affect device reliability .

3. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.

Page 8

Philips Semiconductors Product specification

74LV4799Timer for NiCd and NiMH chargers

1998 Apr 20

DC ELECTRICAL CHARACTERISTICS

Over recommended operating conditions. Voltages are referenced to GND (ground = 0 V).

LIMITS

SYMBOL PARAMETER TEST CONDITIONS

+25°C 0°C to +70°C

UNIT

MIN TYP MAX MIN MAX

VCC = 1.0 V 0.8 0.5 – 0.8 –

HIGH level Input voltage

VCC = 4.5 V 3.6 2.4 – 3.6 –

V VCC = 6.0 V 4.8 3.2 – 4.8 – VCC = 1.0 V – 0.5 0.2 – 0.2

LOW level Input voltage

VCC = 4.5 V – 2.1 0.9 – 0.9

V VCC = 6.0 V – 2.8 1.2 – 1.2

HIGH level output voltage;

VCC = 1.0 V; VI = VIH or V

IL;

IO = –190µA 0.90 0.96 – 0.89 –

RC, RD outputs

VCC = 6.0 V; VI = VIH or V

IL;

IO = –6.1mA 5.73 5.84 – 5.66 –

HIGH level output voltage;

VCC = 1.0 V; VI = VIH or V

IL;

IO =–24µA 0.90 0.96 – 0.89 –

RS output

VCC = 6.0 V; VI = VIH or V

IL;

IO =–760µA 5.73 5.84 – 5.66 –

LOW level output voltage;

VCC = 1.0 V; VI = VIH or V

IL;

IO = 190µA – 0.04 0.10 – 0.11

RC, RD outputs

VCC = 6.0 V; VI = VIH or V

IL;

IO = 6.1mA – 0.16 0.26 – 0.33

LOW level output voltage;

VCC = 1.0 V; VI = VIH or V

IL;

IO =24µA – 0.04 0.10 – 0.11

RS output

VCC = 6.0 V; VI = VIH or V

IL;

IO =760µA – 0.16 0.26 – 0.33

LOW level output voltage;

VCC = 1.0 V; VI = VIH or V

IL;

IO = 220µA – 0.04 0.10 – 0.11

MOLLI, LED outputs

VCC = 6.0 V; VI = VIH or V

IL;

IO = 7.4mA – 0.17 0.26 – 0.33

LOW level output voltage;

VCC = 1.0 V; VI = VIH or V

IL;

IO =360µA;

pin 4 open

– 0.04 0.10 – 0.11

EN output

VCC = 6.0 V; VI = VIH or V

IL;

IO =13.0mA;

pin 4 open

– 0.17 0.26 – 0.33

LOW level output voltage; EN output

VCC = 1.3 V; VI = VIH or V

IL;

pin 4 = 10 V

– 0.12 0.35 – 0.40

LOW level output voltage;

VCC = 1.0 V; VI = VIH or V

IL;

IO =140µA;

pin 4 HIGH

– 0.04 0.10 – 0.11

EN output

VCC = 6.0 V; VI = VIH or V

IL;

IO =5.0mA;

pin 4 HIGH

– 0.17 0.26 – 0.33

POR level active inactive

0.25 –

– –

0.65

0.9

– –

Quiescent supply current

VCC = 6.0 V; VI = VCC or GND; pins 5, 14, and 15 at GND; pins 7 and 9 at V

– 34 50 – 400 µA

Input leakage current pins 4 and 9

VCC = 1.0 V; VI = 10 V – – 500 – –

Input leakage current pins 14 and15

VCC = 6.0 V; VI = VCC or GND – – 100 – –

VCC = 1.0 V; VI = GND –0.5 –2.4 –10 – –

Pull-u current in 7

VCC = 6.0 V; VI = GND –0.5 –2.4 –10 – –

VCC = 1.0 V; VI = V

0.5 2.4 10 – –

µA

Pull-down current in 5

VCC = 6.0 V; VI = V

0.5 2.4 10 – –

OFF-state current pin 1, 3, and 6

VCC = 6.0 V; VI = VIH or V IL; VO = 10 V – – 500 – –

OZH

OFF-state current pin 2 VCC = 6.0 V; VO = 6 V; Vin = open – – 100 – –

OFF-state current pin 3 VCC = 6.0 V; VI = VIH or V IL; VO = 6 V – – 100 – –

OFF-state current pins 10, 11, and 12

VCC = 6.0 V; VI = VIH or V IL; VO = VCC or GND

– – ±100 – – nA

NOTE:

1. This item guarantees that an external bipolar NPN-transistor can be switched off by the EN output.

2. Oscillator disabled. This can be done by I

= HIGH or LOW.

Page 9

Philips Semiconductors Product specification

74LV4799Timer for NiCd and NiMH chargers

1998 Apr 20

AC CHARACTERISTICS

GND = 0V; tr = tf ≤ 2.5ns; CL = 50pF

amb

(°C)

SYMBOL PARAMETER

TEST CONDITIONS

+25 0 to +70

UNIT

VCC(V) MIN TYP MAX MIN MAX

1.0

Any resistor or capacitor according to

–11 –4 +3

∆f

Oscillator frequency s read

6.0

the application information, see note 1

–9 –2 +5

1.0

– 50

LED

Duty factor at in 1

6.0

See Note 2

– 50

1.0

– 50

MOLLI

Duty factor at in 6

6.0

See Note 3

– 50

1.0 – 67

deb

Debounce su ression at in 9

6.0 – 65

Maximum frequency at power

1.0 100

i(max)

sense input

6.0 100

kHz

Minimum frequency at power

1.0 50

i(min)

sense input

6.0 50

NOTES:

1. The oscillator frequency can be calculated by:

f 

0.36

R  C1

2. During blinking.

3. An output signal of four periods will appear in case of discharged batteries and DIS

is switched HIGH.

APPLICATION INFORMATION

Oscillator.

The frequency will be determined by the external components R

, RD, RS, and C1. The frequencies can be calculated by the following

expressions:

f 

0.36

 C1

;

f 

0.36

 C1

;

f 

0.36

 C1

and C1 determine the charge time.

and C1 determine the discharge time.

and C1 determine the self-charge time.

The charge, discharge and self-discharge times can be calculated as follows:

Charge time 

;

Discharge time 

;

Self-discharge time 

In the trickle charge mode, the average charge current will be reduced by a factor:

1 

3xR

4xR

External components range

amb

(°C)

SYMBOL PARAMETER

TEST CONDITIONS

+25

UNIT

VCC(V) V

OTHER MIN TYP MAX

1.0 5.360 100

2.0

1.150 100

k

RC/R

Resistor range

4.5

= 0.22

µF

0.562 100

6.0 0.511 100

k

1.0 42.20 825

2.0

9.09 825

k

Resistor range

4.5

= 0.22

µF

4.22 825

6.0 3.32 825

k

1.0 no limit p

2.0 no limit

Ca acitor range

4.5 no limit p

6.0 no limit

Page 10

Philips Semiconductors Product specification

74LV4799Timer for NiCd and NiMH chargers

1998 Apr 20

Charge discharge times

PARAMETER

TIME RANGE CONDITIONS

Charge time 4 hours to 16 hours Discharge time 15 minutes to to 4.7 hours

omponents ranges are w

ithin th

e values

iven in Section “External components range”

Self-discharge time 50 days to 100 days

given in Section External com onents range

LED frequency

The frequency of the LED

output (pin1) is determined by the oscillator frequency.

Three modes of operation, each with its own frequency, are possible.



256

Mode SEL LED frequency

Charge

Trickle charge

Alarm

H or open

MOLLI

pulse duration

The MOLLI output gives an output signal of four periods with a 50% duty cycle. The duration of one period is determined by: 16/f

Timing accuracy .

The timing accuracy depends on the accuracy of the on–chip oscillator and on the external R and C components. The inaccuracy of the on–chip oscillator is specified as maximum +/–7%. In most cases the actual inaccuracy will be significantly lower. This depends on the supply voltage as well as the value of the external components.

Influence of Resistor value.

Low resistor values cause some spread because the RC combination is biased by a 3–State push–pull output. The spread of

the R

of the push–pull stage will contribute to the frequency spread. When high–value resistors are used, any possible output leakage of the not–selected 3–State outputs will cause a frequency deviation. For these reasons, the resistor values must be within the specified ranges.

Influence of supply voltage

The trip levels of the oscillator are fixed at 20% and 80% of V

. At higher supply voltages the spread of the trip levels decreases in greater proportion because the offset voltage remains constant, and the propagation delay decreases. Furthermore, the R

values of

the push–pull driving stage decrease at higher voltages.

SPREAD-CAUSING FACTORS

amb

(°C)

SYMBOL

PARAMETER

(V)

MIN TYP MAX

UNIT

1.0 7 mV

off

Offset voltage

6.0 7 mV

1.0 22

Pro agation delay

6.0 5.5

1.0 170

P-channel resistance R

out uts

6.0 25

1.0 250

N-channel resistance R

out uts

6.0 35

1.0 1300

P-channel resistance R

out ut

6.0 180

1.0 1300

N-channel resistance R

out ut

6.0 180

Page 11

Philips Semiconductors Product specification

74LV4799Timer for NiCd and NiMH chargers

1998 Apr 20

Error free operation, even under extreme conditions.

Several measures are taken in the circuit design to ensure error–free operation, even with very low supply voltages. Moreover, the circuit has been made very insensitive to the effects of external fields. The measures taken during the design are:

•Use of synchronous logic

•Bistable POR instead of monostable POR

•Data retention assured below a supply voltage of 0.9 V .

•Debounce circuitry on DIS input (maximum expected debounce

time = 10 ms)

•Schmitt trigger on PWRS (power sense) input and on DIS input

•Special oscillator security to prevent any malfunction.

Synchronous logic and bistable POR.

Use of synchronous logic results in much lower sensitivity to spikes on input pins. The POR is adapted to fit well into a synchronous environment. An increasing supply voltage sets the POR. The POR output signal is routed to the control logic and divider/counter. it is synchronized with the on–chip clock. After all flip–flops are reset, a reset acknowledge signal is generated which resets the POR. This method ensures that the POR signal is acknowledged in all cases, even at very low voltages.

Data retention.

The circuit may be used in an application where an electric motor is present. When the motor is switched on, it will disturb the supply voltage for a short period. The POR level is set at such a level that, even with very low supply voltages, the POR will not respond during motor switch on. The flip–flops will retain their data during the supply voltage disturbance because of the inherent data retention of any CMOS gate. However, when the battery is almost completely discharged and the motor switch is activated, the dip on the supply voltage line can be too large. The retention of the POR is therefore made deliberately worse than that of the internal flip–fops. The POR will therefore respond long before the flip–flops will loose their data. This results in a proper start condition for a new charge cycle.

Debounce circuitry on DIS

input.

A discharge cycle is activated by a switch. To protect the circuit from any bounce of the switch contacts, de–bounce circuitry is provided

at the DIS

input. The circuitry allows a switch de–bounce time of

max. 10 ms.

Schmitt trigger on PWRS (power sense) input.

The PWRS input can be corrupted by high transients due to disturbances on the mains supply. To suppress any false triggering, the PWRS input is provided with a Schmitt–trigger. However, for some applications, it is advisable to connect a low–value capacitor (150 pF min.) between the PWRS input and GND.

Special oscillator security to prevent any malfunction.

The excellent performance of the oscillator is achieved by using linear op–amp techniques. The oscillator consists of an internal reference, two comparators and a latch. Care was taken to design a very reliable oscillator even with a supply voltage below 0.9 V . If one of the comparators ceases to operate with a supply voltage below

0.9 V , the latch will not be corrupted. Priority was given to stop the oscillator rather than allow uncontrolled oscillation.

All these measures result in reliable 1-cell to 4-cell battery charge management.

Remaining energy indication:

The scan test facility can be used as a remaining energy indication because the value of the counter can be read–out at the scan output (MOLLI

/SCO). This is achieved by briefly interrupting the normal mode of operation, putting the circuit in the scan mode (pin 14 = HIGH), and reading–out of the counter value. The circuit is then returned to the normal mode (pin 14 = LOW or open).

Read–out procedure: The contents of the counter flip–flops can be read–out in the scan mode. To ensure that there is no disturbance of the circuit function, it is essential to either create a round coupled loop by linking the MOLLI

/SCO output (pin 6) directly to the SCI input pin 15), or to shift–in the serial data of the scan line at the SCI input after completion of the read out cycle. 49 clock pulses are needed on the Iosc input (pin 13) to shift–out the contents of the whole scan line. The most–significant bit of the counter will appear at the MOLLI

/SCO output after the last clock pulse. The least–significant bit after the penultimate clock pulse, etc. Selecting the last three or four bits will yield sufficiently high accuracy to obtain the counter value which represents the remaining energy of the battery.

SV01647

SCI

SCAN

SEL

PWRS

LED

n.c.

MOLLI

DIS

7 14 15

10 11 12 13 8

RDRSI

OSC

LOAD

battery

buzzer

74LV4799

220 V

110 V

mains

BC557

BYD13D

BZD23

BYD13D

BZD23

BYD13D BYD13D

BC547

BC327/ BC636

BC557

Figure 2. Typical application of the low-voltage 74LV4799.

Page 12

Philips Semiconductors Product specification

74LV4799Timer for NiCd and NiMH chargers

1998 Apr 20

SV01648

GNDSEL

PWRS

100–240 VAC 12/24 VDC

DRN

VAT

SRC

VIC

GNDC

VAC2 VAC1 PWR/LED EN

1.0 mH

33E

TR1

2µ2

10µ

1µF

DIS

LED

20 16

15 14 13

10 11 12 13

RDRSI

OSC

LOAD

74LV4799

TEA1400

1µF

2µ2

Figure 3. Application diagram of the 74LV4799 in combination with the high-voltage IC TEA1400.

SV01649

SCI

SCAN

SEL

PWRS

DIS

GND

LED

7 14 15

10 11 12 13 8 166

RDRSI

OSC

LOAD

battery

74LV4799

Option A: At V

> 2.0 V Q1 may

be directly biased by EN

Option B: At V

< 2.0 V add

an extra NPN transistor (Q2)

BYD13D

MOLLI/

SCO

Figure 4. Inductive loader, showing the two options A and B.

Page 13

Philips Semiconductors Product specification

74LV4799

Timer for NiCd and NiMH chargers

1998 Apr 20

DIP16: plastic dual in-line package; 16 leads (300 mil) SOT38-4

Page 14

Philips Semiconductors Product specification

74LV4799

Timer for NiCd and NiMH chargers

1998 Apr 20

SO16: plastic small outline package; 16 leads; body width 3.9 mm SOT109-1

Page 15

Philips Semiconductors Product specification

74LV4799

Timer for NiCd and NiMH chargers

1998 Apr 20

SSOP16: plastic shrink small outline package; 16 leads; body width 5.3 mm SOT338-1

Page 16

Philips Semiconductors Product specification

74LV4799

Timer for NiCd and NiMH chargers

1998 Apr 20

TSSOP16: plastic thin shrink small outline package; 16 leads; body width 4.4 mm SOT403-1

Page 17

Philips Semiconductors Product specification

74LV4799

Timer for NiCd and NiMH chargers

1998 Apr 20

NOTES

Page 18

Philips Semiconductors Product specification

74LV4799Timer for NiCd and NiMH chargers

yyyy mmm dd

Definitions

Short-form specification — The data in a short-form specification is extracted from a full data sheet with the same type number and title. For

detailed information see the relevant data sheet or data handbook. Limiting values definition — Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one

or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability.

Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or modification.

Disclaimers

Life support — These products are not designed for use in life support appliances, devices or systems where malfunction of these products can

reasonably be expected to result in personal injury . Philips Semiconductors customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application.

Right to make changes — Philips Semiconductors reserves the right to make changes, without notice, in the products, including circuits, standard cells, and/or software, described or contained herein in order to improve design and/or performance. Philips Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless otherwise specified.

Philips Semiconductors 811 East Arques Avenue P.O. Box 3409 Sunnyvale, California 94088–3409 Telephone 800-234-7381

 Copyright Philips Electronics North America Corporation 1998

print code Date of release: 05-96 Document order number: 9397-750-04664

 

Data sheet status

Objective specification

Preliminary specification

Product specification

Product status

Development

Qualification

Production

Definition

[1]

This data sheet contains the design target or goal specifications for product development. Specification may change in any manner without notice.

This data sheet contains preliminary data, and supplementary data will be published at a later date. Philips Semiconductors reserves the right to make chages at any time without notice in order to improve design and supply the best possible product.

This data sheet contains final specifications. Philips Semiconductors reserves the right to make changes at any time without notice in order to improve design and supply the best possible product.

Data sheet status

[1] Please consult the most recently issued datasheet before initiating or completing a design.