Philips TEA1200TS User Manual

查询TEA1200TS供应商查询TEA1200TS供应商

INTEGRATED CIRCUITS

DATA SH EET

TEA1200TS

0.95 V starting DC-to-DC converter with low battery indicator

Product speciﬁcation 2002 May 14

Philips Semiconductors Product speciﬁcation

0.95 V starting DC-to-DC converter with low battery indicator

FEATURES

• Complete DC-to-DC converter circuit and battery low detector

• Configurablefor1, 2 or 3-cellNickel-Cadmium(NiCd)or Nickel Metal Hydride (NiMH) batteriesand 1 LithiumIon (Li-Ion) battery

• Guaranteed DC-to-DC converter start-up from 1-cell NiCd or NiMH battery, even with a load current

• Upconversion or downconversion

• Internal power MOSFETs featuring a low R approximately 0.1 Ω

• Synchronous rectification for high efficiency

• Soft start

• PWM-only operating option

• Stand-alone low battery detector requires no additional

supply voltage

• Low battery detection level at 0.90 V, externally adjustable to a higher level

• Adjustable output voltages

• Shut-down function

• Small outline package

• 0.6 µm BICMOS process.

APPLICATIONS

• Cellular phones

• Cordless phones

• Personal Digital Assistants (PDAs)

• Portable audio players

• Pagers

• Mobile equipment.

DSon

TEA1200TS

GENERAL DESCRIPTION

The TEA1200TS is a fully integrated battery power unit including a high-efficiency DC-to-DC converterwhich runs from a 1-cell NiCd or NiMH battery and a low battery detector. The circuit can be arranged in several ways to optimize the application circuit of a power supply system. Therefore, the DC-to-DC converter can be arranged for upconversion or downconversion and the low battery detector can be configured for several types of batteries. Accurate low battery detection is possible while all other blocks are switched off.

The DC-to-DC converter features efficient, compact and dynamic power conversion using a digital control concept comparable with Pulse Width Modulation (PWM) and Pulse Frequency Modulation (PFM), integrated CMOS power switches with a very low R synchronous rectification.

The device operates at a switching frequency of 600 kHz which enables the use of external components with minimum size. The switching frequency can be synchronized to an external high frequency clock signal. Optionally, the device can be kept in PWM control mode only. Deadlock is prevented by an on-chip undervoltage lockout circuit.

Active current limiting enables efficient conversion in pulsed-load systems such as Global System for Mobile communication (GSM) and Digital Enhanced Cordless Telecommunications (DECT).

The low battery detector has a built-in detection level which is optimum for a 1-cell NiCd or NiMH battery.

DSon

and fully

ORDERING INFORMATION

TYPE

NUMBER

TEA1200TS SSOP16 plastic shrink small outline package; 16 leads; body width 4.4 mm SOT369-1

2002 May 14 2

NAME DESCRIPTION VERSION

PACKAGE

Philips Semiconductors Product speciﬁcation

0.95 V starting DC-to-DC converter TEA1200TS

with low battery indicator

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

DC-to-DC converter

UPCONVERSION V

i(up)

o(up)

i(start)

o(uvlo)

DOWNCONVERSION V

i(dwn)

o(dwn)

CURRENT LEVELS I

q(DC/DC)

shdwn

LX(max)

∆I

lim

POWER MOSFETS R

DSon(N)

DSon(P)

EFFICIENCY η efﬁciency upconversion see Fig.8; Voup to 3.3 V

TIMING f

i(sync)

start

General characteristics

ref

input voltage V output voltage V

− 5.50 V

i(start)

− 5.50 V

o(uvlo)

start-up input voltage IL< 10 mA 0.93 0.96 1.00 V undervoltage lockout voltage note 1 2.0 2.2 2.4 V

input voltage V

− 5.50 V

o(uvlo)

output voltage 1.30 − 5.50 V

quiescent current at pin

− 110 −µA

UPOUT/DNIN current in shut-down mode V maximum continuous current at

LBI1=VI(up)

=80°C −−1.0 A

amb

= 1.2 V − 65 −µA

pins LX1 and LX2 current limit deviation I

set to 1.0 A

lim

upconversion −12 − +12 % downconversion −12 − +12 %

drain-to-sourceon-state resistance

Tj=27°C; IDS= 100 mA − 110 200 mΩ

NFET drain-to-sourceon-state resistance

Tj=27°C; IDS= 100 mA − 125 250 mΩ

PFET

= 1.2 V; IL= 100 mA − 84 − %

= 2.4 V; IL=10mA − 92 − %

switching frequency PWM mode 480 600 720 kHz synchronization clock input

6 1320MHz

frequency start-up time − 10 − ms

reference voltage 1.165 1.190 1.215 V

Note

1. The undervoltage lockoutlevel showswide specification limits since it decreases withincreasing temperature.When the temperature increases, the minimum supply voltage of the digital control part of the IC decreases and therefore thecorrect operation of this functionis guaranteed overthe whole temperaturerange. The undervoltagelockout level is measured at pin UPOUT/DNIN.

2002 May 14 3

Philips Semiconductors Product speciﬁcation

0.95 V starting DC-to-DC converter with low battery indicator

BLOCK DIAGRAM

UPOUT/DNIN

n.c.

UPOUT/DNIN

INTERNAL

SUPPLY

GND

TEA1200TS

FB0

ref

VOLT AGE

REFERENCE

ref

MBL409

TEA1200TS

TIME

COUNTER

AND

CIRCUIT

START-UP

sense FET

P-type POWER FET

DETECTOR

LOW BATTERY

MODE GEARBOX

CONTROL LOGIC

COMPARATOR

CURRENT LIMIT

ref

TEMPERATURE

N-type

POWER

PROTECTION

FET

sense

DIGITAL CONTROLLER

GATE

SYNC

13 MHz

OSCILLATOR

SHDWN0

1413 2 15

SYNC/PWM U/D

GND0

Fig.1 Block diagram.

handbook, full pagewidth

This text is here in white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader.This text is here in

_white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader.This text is here inThis text is here in

white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader. white to force landscape pages to be ...

2002 May 14 4

LBI1

LBO

LX1

LX2

ILIM

Philips Semiconductors Product speciﬁcation

0.95 V starting DC-to-DC converter with low battery indicator

PINNING

SYMBOL PIN DESCRIPTION

LX1 1 inductor connection 1 SHDWN0 2 DC-to-DC converter shut-down

input

UPOUT/DNIN 3 up mode: DC-to-DC converter

output; down mode DC-to-DC converter input

UPOUT/DNIN 4 up mode: DC-to-DC converter

output; down mode DC-to-DC converter input

ILIM 5 current limiting resistor

connection n.c. 6 not connected V

ref

GND 8 internal supply ground LBI1 9 low battery detector input 1 LBO 10 low battery detector output V

ref

FB0 12 DC-to-DC converter feedback

GND0 13 DC-to-DC converter ground SYNC/PWM 14 synchronization clock input or

U/D 15 conversion mode selection input LX2 16 inductor connection 2

7 reference voltage input

11 reference voltage input

input

PWM-only selection input

handbook, halfpage

UPOUT/DNIN UPOUT/DNIN

LX1

SHDWN0

ILIM

n.c.

ref

GND

2 3 4

TEA1200TS

5 6 7 8

Fig.2 Pin configuration.

TEA1200TS

LX2

U/D

15 14

SYNC/PWM

GND0

FB0

ref

LBO

LBI1

MBL419

FUNCTIONAL DESCRIPTION Control mechanism

The TEA1200TS DC-to-DC converter is able to operate in the PFM (discontinuous conduction) or PWM (continuous conduction) operating mode. All switching actions are completely determined by a digital control circuit which usesthe output voltage levelasits control input. Thisnovel digital approach enables the use of a new pulse width and frequency modulation scheme, which ensures optimum power efficiency over the complete range of operation of the converter.

When high output power is requested, the device will operate in the PWM operating mode. This results in minimumAC currents in the circuitcomponentsandhence optimum efficiency, minimum costs and low EMC. In this operating mode, the output voltage is allowed to vary between two predefined voltage levels. As long as the output voltage stays within this so-called window, switching continues in a fixed pattern.

2002 May 14 5

When the output voltage reaches one of the window borders, the digital controller immediately reacts by adjusting the pulse width and inserting a current step in such a waythat the output voltage stayswithin the window with higher or lower current capability. This approach enables very fast reaction to load variations. Figure 3 shows the response of the converter to a sudden load increase. The upper trace shows the output voltage.

The ripple on top of the DC level is a result of the current in the output capacitor, which changes in sign twice per cycle, times the internal Equivalent Series Resistance (ESR) of the capacitor. After each ramp-down of the inductor current, i.e. when the ESR effect increases the output voltage, the converter determines what to do in the next cycle. As soon as more load current istaken from the output the output voltage starts to decay.

Philips Semiconductors Product speciﬁcation

0.95 V starting DC-to-DC converter with low battery indicator

When the output voltage becomes lower than the low limit of the window, a corrective actionis taken by a ramp-up of theinductor current duringa much longertime. As aresult, the DC current level is increasedand normalPWM control can continue. The output voltage (including ESR effect) is again within the predefined window.

Figure 4 shows the spread of the output voltage window. The absolute value is mostly dependent on spread, while the actual window size [V

wdw(high)

affected. For one specific device, the output voltage will not vary more than 2% (typical value).

handbook, full pagewidth

− V

wdw(low)

load increase

] is not

start corrective action

TEA1200TS

In low output power situations, the TEA1200TS will switch over to PFM operating mode. In this mode, regulation information from an earlier PWM operating mode is used. This results in optimum inductor peak current levels in the PFM mode, which are slightly larger than the inductor ripple current in the PWM mode. As a result, the transition between PFM and PWM mode is optimum under all circumstances. In the PFM mode the TEA1200TS regulates the output voltage to the high window limit as shown in Fig.3.

high window limit

low window limit

time

MGK925

Fig.3 Response to load increase.

2002 May 14 6

Philips Semiconductors Product speciﬁcation

0.95 V starting DC-to-DC converter with low battery indicator

handbook, full pagewidth

O (typ)

wdw(high)

wdw(low)

typical situation

maximum positive spread of V

+2%

wdw(high)

wdw(low)

maximum negative spread of V

−2%

wdw(high)

wdw(low)

upper specification limit

lower specification limit

TEA1200TS

MGU269

Fig.4 Output voltage window spread.

Synchronous rectiﬁcation

For optimum efficiency over the whole load range, synchronous rectifiers within the TEA1200TS ensure that during the whole second switching phase, all inductor current will flow through the low-ohmic power MOSFETs. Special circuitry is included which detects when the inductorcurrentreaches zero. Followingthisdetection,the digital controller switches off the power MOSFET and proceeds with regulation.

Start-up

Start-up from low input voltage in the boost mode is realized by anindependent start-up oscillator,which starts switching the N-type power MOSFET as soon as the low-battery detector detects a sufficiently high voltage. The inductor current is limited internally to ensure soft-starting. The switch actions of the start-up oscillator will increase the output voltage. As soon as the output voltage is high enough for normal regulation, the digital control system will take control over the power MOSFETs.

Undervoltage lockout

As a result of too high a load or disconnection of the input power source, the output voltage can drop so low that normal regulation cannot beguaranteed. In this event, the device switches back to start-up mode. If the output voltage drops even further, switching is stopped completely.

Shut-down

When the shut-down input is set HIGH, the DC-to-DC converter disables both switches and power consumption is reduced to a few microamperes.

Power switches

The power switches in the IC are one N-type and one P-type power MOSFET, both having a typical drain-to-source resistance of 100 mΩ. The maximum continuous current in the power switches is 1.0 A at T

=80°C.

amb

2002 May 14 7

Philips Semiconductors Product speciﬁcation

0.95 V starting DC-to-DC converter with low battery indicator

Temperature protection

When the DC-to-DC converter operates in the PWM mode, and thedie temperaturegets toohigh (typical value is 190 °C), the converter will stop operating. It resumes operation when the die temperature falls below 90 °C again. As a result, low frequency cycling between the on and off state willoccur. It should be noted that in the event of device temperatures at the cut-off limit, the application differs strongly from maximum specifications.

Current limiters

If the current in one of the power switches exceeds the programmed limit in the PWM mode, the current ramp is stopped immediately and the next switching phase is entered. Current limiting is required to keep power conversion efficient during temporary high loads. Furthermore, current limiting protects the IC against overload conditions, inductor saturation, etc.

The current limiting level is set by an external resistor whichmust be connected betweenpin ILIMand ground for downconversion, or betweenpins ILIM and UPOUT/DNIN for upconversion.

External synchronization and PWM-only mode

If an external high-frequency clock or a HIGH level is applied to pin SYNC/PWM, the TEA1200TSwill usePWM regulation independent of the load applied.

In the event that a high-frequency clock is applied, the switching frequency in the PWM mode will be exactly that frequency divided by 22. In the PWM mode the quiescent current of the device increases.

In the event that no external synchronization or PWM mode selection is necessary, pin SYNC/PWM must be connected to ground.

TEA1200TS

Behaviour when the input voltage exceeds the speciﬁed range

In general, an inputvoltage exceeding the specified range isnot recommended sinceinstability may occur.There are two exceptions:

1. Upconversion: at an input voltage higher than the targetoutput voltage, butupto 5.5 V, theconverter will stop switching and the external Schottky diode will take over. The output voltage will equal the input voltageminus thediode voltage drop.Since all current flows through the external diode in this situation, the current limiting function is not active.

In the PWM mode, the P-type power MOSFET is always on when the input voltage exceeds the target output voltage. The internal synchronous rectifier ensures that the inductor current does not fall below zero. As a result, the achieved efficiency is higher in this situation than standard PWM-controlled converters achieve.

2. Downconversion: when the input voltage islower than the target output voltage, but higher than 2.2 V, the P-type power MOSFET will stay conducting resulting in the output voltage being equal to the input voltage minussomeresistive voltage drop. Thecurrentlimiting function remains active.

Low battery detector

The low battery detector is an autonomous circuit which can work at an input voltage down to 0.90 V. It is always on, even when all other blocks are in the shut-down mode.

The low battery input (pin LBI1) is adjusted to accept a 1-cell NiCd or NiMH battery voltage directly. Hysteresis is included for proper operating.

The output of the low battery detector (pin LBO) is an open-collector output. The output is high (i.e. no current is sunk by the collector) when the input voltage of the detector is below the lower detection level.

2002 May 14 8

+ 16 hidden pages