TEXAS INSTRUMENTS TL5002 Technical data

查询TL5002供应商

TL5002

PULSE-WIDTH-MODULATION CONTROL CIRCUIT

SLVS304A – SEPTEMBER 2000 – REVISED AUGUST 2002

CC

D PACKAGE

(TOP VIEW)

1
2
3
4

8
7
6
5

GND
RT
DTC
NI

D Complete PWM Power Control
D 3.6-V to 40-V Operation
D Internal Undervoltage-Lockout Circuit
D Oscillator Frequency . . . 20 kHz to 500 kHz
D Variable Dead Time Provides Control Over

Total Range

OUT

V

COMP

INV

D Ideal Controller for DDR Memory

Application

D Uncommitted Error Amplifier Inputs

description

The TL5002 incorporates on a single monolithic chip all the functions required for a pulse-width-modulation
(PWM) control circuit. Designed primarily for power-supply control, the TL5002 contains an error amplifier, a
regulator, an oscillator, a PWM comparator with a dead-time-control input, undervoltage lockout (UVLO), and
an open-collector output transistor.

The error-amplifier input common-mode voltage ranges from 0.9 V to 1.5 V. Dead-time control (DTC) can be
set to provide 0% to 100% dead time by connecting an external resistor between DTC and GND. The oscillator
frequency is set by terminating RT with an external resistor to GND. During low V
turns the output off until V

recovers to its normal operating range.

CC

The TL5002 is characterized for operation from –40°C to 85°C.

AVAILABLE OPTIONS

T

A

–20°C to 85°C TL5002CD
–40°C to 85°C TL5002ID

The D package is available taped and reeled. Add the suffix R
to the device type (e.g., TL5002CDR).

SMALL OUTLINE

(D)

conditions, the UVLO circuit

CC

functional block diagram

V

Reference

Error
Amplifier

5

NI

INV

COMP

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.

+

4

–

3

Voltage

CC

2

UVLO

2.5 V

RT

OSC

I

DT

DTC

67

PWM/DTC
Comparator

Copyright  2002, Texas Instruments Incorporated

OUT

GND

1

8

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

1

TL5002
PULSE-WIDTH-MODULATION CONTROL CIRCUIT

SLVS304A – SEPTEMBER 2000 – REVISED AUGUST 2002

detailed description

voltage reference

A 2.5-V regulator operating from V

is used to power the internal circuitry of the TL5002.

CC

error amplifier

The error amplifier compares a sample of the dc-to-dc converter output voltage to an external reference voltage
and generates an error signal for the PWM comparator. The dc-to-dc converter output voltage is set by selecting
the error-amplifier gain (see Figure 1), using the following expression:

= (1 + R1/R2) (1 V)

V

O

TL5002

–

+

To PWM
Comparator

Compensation

V

I(FB)

Network

R1

R2

3

COMP

4

INV

5

ref

NI

GND8

V

Figure 1. Error-Amplifier Gain Setting

The error-amplifier output is brought out as COMP for use in compensating the dc-to-dc converter control loop
for stability . Because the amplifier can only source 45 µA, the total dc load resistance should be 100 kΩ or more.

oscillator/PWM

The oscillator frequency (f

) can be set between 20 kHz and 500 kHz by connecting a resistor between RT

osc

and GND. Acceptable resistor values range from 15 kΩ to 250 kΩ. The oscillator frequency can be determined
by using the graph shown in Figure 5.

The oscillator output is a triangular wave with a minimum value of approximately 0.7 V and a maximum value
of approximately 1.3 V. The PWM comparator compares the error-amplifier output voltage and the DTC input
voltage to the triangular wave and turns the output transistor off whenever the triangular wave is greater than
the lesser of the two inputs.

dead-time control (DTC)

DTC provides a means of limiting the output-switch duty cycle to a value less than 100%, which is critical for
boost and flyback converters. A current source generates a reference current (I

) at DTC that is nominally

DT

equal to the current at the oscillator timing terminal, RT . Connecting a resistor between DTC and GND generates
a dead-time reference voltage (V
as described in the previous section. Nominally , the maximum duty cycle is 0% when V
100% when V

is 1.3 V or greater. Because the triangle wave amplitude is a function of frequency and the

DT

source impedance of RT is relatively high (1250 Ω), choosing R

), which the PWM/DTC comparator compares to the oscillator triangle wave

DT

for a specific maximum duty cycle, D, is

DT

is 0.7 V or less and

DT

accomplished using the following equation and the voltage limits for the frequency in question as found in
Figure 11 (V

max and V

osc

min are the maximum and minimum oscillator levels):

osc

2

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

dead-time control (DTC) (continued)

TL5002

PULSE-WIDTH-MODULATION CONTROL CIRCUIT

SLVS304A – SEPTEMBER 2000 – REVISED AUGUST 2002

ǒ

Ǔ

–e

1

ƪ

DǒV

ǒ

–tńRDTC

C

max – V

osc

DT

DT

Figure 2. Soft-Start Circuit

osc

Ǔ

Ǔ

R

6

DT

minǓ) V

DTC

osc

TL5002

R

Where

R

DT

Soft start can be implemented by paralleling the DTC resistor with a capacitor (C
soft start, the voltage at DTC is derived by the following equation:

VDT[ IDTR

If the dc-to-dc converter must be in regulation within a specified period of time, the time constant, R
should be t
every time UVLO becomes active.

undervoltage-lockout (UVLO) protection

ǒ

+

DT

Rt) 1250

and Rt are in ohms, D in decimal

DT

/3 to t0/5. The TL5002 remains off until VDT ≈ 0.7 V, the minimum ramp value. CDT is discharged

0

min

ƫ

) as shown in Figure 2. During

DT

DTCDT

,

The undervoltage-lockout circuit turns the output transistor off whenever the supply voltage drops too low
(approximately 3 V at 25°C) for proper operation. A hysteresis voltage of 200 mV eliminates false triggering on
noise and chattering.

output transistor

The output of the TL5002 is an open-collector transistor with a maximum collector current rating of 21 mA and
a voltage rating of 51 V. The output is turned on under the following conditions: the oscillator triangle wave is
lower than both the DTC voltage and the error-amplifier output voltage, and the UVLO circuit is inactive.

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

3

TL5002
PULSE-WIDTH-MODULATION CONTROL CIRCUIT

SLVS304A – SEPTEMBER 2000 – REVISED AUGUST 2002

absolute maximum ratings over operating free-air temperature range (unless otherwise noted)

Supply voltage, V
Amplifier input voltage, V
Output voltage, V
Output current, I
Output peak current, I

Continuous total power dissipation See Dissipation Rating Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operating ambient temperature range, T
Storage temperature range, T

Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds 260°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

†

Stresses beyond those listed under “absolute maximum ratings” 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 indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

NOTE 1: All voltage values are with respect to network ground terminal.

PACKAGE

D 725 mW 5.8 mW/°C 464 mW 377 mW 145 mW

(see Note 1) 41 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CC

, OUT 51 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

O

, OUT 21 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

O

O(peak)

TA ≤ 25°C

POWER RATING

V

I(INV),

20 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I(NI)

, OUT 100 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–40°C to 85°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

stg

A

DISSIPATION RATING TABLE

DERATING FACTOR

ABOVE TA = 25°C

TA = 70°C

POWER RATING

TA = 85°C

POWER RATING

TA = 125°C

POWER RATING

recommended operating conditions

MIN MAX UNIT

Supply voltage, V
Amplifier input voltage, V
Output voltage, VO, OUT 50 V
Output current, IO, OUT 20 mA
COMP source current 45 µA
COMP dc load resistance 100 kΩ
Oscillator timing resistor, R
Oscillator frequency, f
Operating ambient temperature, T

CC

I(INV), VI(NI)

t

osc

A

3.6 40 V

0.9 1.5 V

15 250 kΩ
20 500 kHz

–40 85 °C

†

4

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

TL5002

Frequency change with tem erature

PULSE-WIDTH-MODULATION CONTROL CIRCUIT

SLVS304A – SEPTEMBER 2000 – REVISED AUGUST 2002

electrical characteristics over recommended operating free-air temperature range, VCC = 6 V,
f

= 100 kHz (unless otherwise noted)

osc

undervoltage lockout

PARAMETER TEST CONDITIONS

Upper threshold voltage TA = 25°C 3 V
Lower threshold voltage TA = 25°C 2.8 V
Hysteresis TA = 25°C 100 200 mV

†

All typical values are at TA = 25°C.

oscillator

PARAMETER TEST CONDITIONS

Frequency Rt = 100 kΩ 100 kHz
Standard deviation of frequency 15 kHz
Frequency change with voltage VCC = 3.6 V to 40 V 1 kHz

TA = –40°C to 25°C –4 –0.4 4 kHz

Frequency change with temperature

Voltage at RT 1 V

†

All typical values are at TA = 25°C.

TA = –20°C to 25°C –4 –0.4 4 kHz
TA = 25°C to 85°C –4 –0.2 4 kHz

TL5002C

MIN TYP†MAX

TL5002C

MIN TYP†MAX

UNIT

UNIT

dead-time control

PARAMETER TEST CONDITIONS

Output (source) current TL5002 V

p

Input threshold voltage

†

All typical values are at TA = 25°C.

‡

Output source current at RT

= 1.5 V 0.9 × I

(DT)

Duty cycle = 0% 0.5 0.7
Duty cycle = 100% 1.3 1.5

TL5002C

MIN TYP†MAX

RT

‡

1.2 × I

UNIT

RT

error amplifier

PARAMETER TEST CONDITIONS

Input voltage VCC = 3.6 V to 40 V 0.3 1.5 V
Input bias current –160 –500 nA

Output voltage swing
Open-loop voltage amplification 80 dB

Unity-gain bandwidth 1.5 MHz
Output (sink) current V
Output (source) current V

†

All typical values are at TA = 25°C.

Positive 1.5 2.3 V
Negative 0.3 0.4 V

= 1.2 V , COMP = 1 V 100 600 µA

I(INV)

= 0.8 V , COMP = 1 V –45 –70 µA

I(INV)

TL5002C

MIN TYP†MAX

UNIT

µA

V

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

5