Texas Instruments TPS5633EVM-104, TPS5633EVM-111, TPS5625PWPR, TPS5625PWP, TPS5625EVM-105 Datasheet

TPS5615, TPS5618, TPS5625, TPS5633

SYNCHRONOUS-BUCK HYSTERETIC REGULATOR CONTROLLER

SLVS177A – SEPTEMBER 1998 – REVISED NOVEMBER 1998

1

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

D

±1% Reference Over Full Operating

T emperature Range

D

Synchronous Rectifier Driver for >90%

Efficiency

D

Fixed Output Voltage Options of 1.5 V,

1.8 V, 2.5 V, and 3.3 V

D

User-Selectable Hysteretic-T ype Control

D

Low Supply Current...3 mA Typ

D

11.4-V to 13-V Input Voltage Range, V

CC

D

Power Good Output

D

Programmable Soft-Start

D

Overvoltage/Overcurrent Protection

D

Active Deadtime Control

description

The TPS5615 family of synchronous-buck regulator controllers provides an accurate supply voltage to DSPs.

The output voltage is internally set by a resistive divider with an accuracy of 1% over the full operating

temperature range. A hysteretic controller with user-selectable hysteresis is used to dramatically reduce

overshoot and undershoot caused by load transients. Propagation delay from the comparator inputs to the

output drivers is less than 250 ns. Overcurrent shutdown and crossover protection for the output drivers

combine to eliminate destructive faults in the output FETs. PWRGD monitors the output voltage and pulls the

open-collector output low when the output drops below 93% of the nominal output voltage. An overvoltage circuit

disables the output drivers if the output voltage rises 15% above the nominal value. The inhibit pin can be used

to control power sequencing. Inhibit and undervoltage lockout assures that the 12-V supply voltage and system

supply voltage (5 V or 3.3 V) are within proper operating limits before the controller starts. The output driver

circuits include 2-A drivers with internal 8-V gate-voltage regulators that can easily provide sufficient power for

today’s high-powered DSPs. The high-side driver can be configured either as a ground-referenced driver or as

a floating bootstrap driver. The TPS5615 family is available in a 28-pin TSSOP PowerPad package. It operates

over a junction temperature range of 0°C to 125°C.

AVAILABLE OPTIONS

PACKAGE

T

J

OUTPUT VOLTAGE

TSSOP

†

(PWP)

1.5 V TPS5615PWP

°

°

1.8 V TPS5618PWP

0°C

to

125°C

2.5 V TPS5625PWP

3.3 V TPS5633PWP

†

The PWP package is availble taped and reeled. Add R suffix to

device type (e.g., TPS5615PWPR).

Copyright  1998, Texas Instruments Incorporated

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.

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.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

28

27

26

25

24

23

22

21

20

19

18

17

16

15

IOUT

AGND2

OCP

VHYST

VREFB

VSENSE

ANAGND

SLOWST

BIAS

LODRV

LOHIB

DRVGND

LOWDR

DRV

PWRGD

NC

NC

NC

NC

NC

INHIBIT

IOUTLO

LOSENSE

HISENSE

BOOTLO

HIGHDR

BOOT

V

CC

PWP PACKAGE

(TOP VIEW)

NC – No internal connection

PowerPAD is a trademark of Texas Instruments Incorporated.

TPS5615, TPS5618, TPS5625, TPS5633

SYNCHRONOUS-BUCK HYSTERETIC REGULATOR CONTROLLER

SLVS177A – SEPTEMBER 1998 – REVISED NOVEMBER 1998

2

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

functional block diagram

INHIBIT

OCP

SLOWST

IOUT

BIAS

DRV

BOOT

HIGHDR

BOOTLO

LOWDR

DRVGND

HISENSEIOUTLOLOSENSEPWRGDANAGND

CC

V

VREFBAGND2 VSENSEVHYST LODRVLOHIB

_

+

2 V

10 V

UVLO

V

CC

22

3

8

25 4 6 11 10

15 7 28 20

21

19

1

9

14

16

17

18

13

12

_

+

Deglitch

100mV

VOVP

1.15 VREF

VSENSE

S

R

Q

V

CC

Deglitch

Fault

Shutdown

VPGD

0.93 VREF

Rising

Edge

Delay

HIGHIN

HIGHDR

2X

Shutdown

_

+

Bandgap

_

+

I

VREFB

5

Analog

Bias

VREF

Hysteresis

Setting

I

VREFB

_

+

_

+

Hysteresis

Comparator

Shutdown

Slowstart

Comparator

CM Filters

PREREG

DRV REG

V

CC

Analog

Bias

TPS5615, TPS5618, TPS5625, TPS5633

SYNCHRONOUS-BUCK HYSTERETIC REGULATOR CONTROLLER

SLVS177A – SEPTEMBER 1998 – REVISED NOVEMBER 1998

3

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Terminal Functions

TERMINAL

NAME NO.

I/O

DESCRIPTION

AGND2 2 Analog ground (must be connected).

ANAGND 7 Analog ground

BIAS 9 Analog bias pin. A 1-µF capacitor should be connected from BIAS to ANAGND.

BOOT 16 Bootstrap. A 1-µF capacitor should be connected from BOOT to BOOTLO.

BOOTLO 18 Bootstrap low. Connect to the junction of the high-side and low-side FETs for floating drive configuration.

Connect to PGND for ground-reference drive configuration.

DRV 14 Drive regulator for the FET drivers. A 1-µF capacitor should be connected from DRV to DRVGND.

DRVGND 12 Drive ground. Ground for FET drivers. Connect to FET PWRGND.

HIGHDR 17 High drive. Output drive to high-side power switching FETs.

HISENSE 19 High current sense. For current sensing across high-side FET s, connect to the drain of the high-side FETs;

for optional current sensing scheme, connect to power supply side of current-sense resistor placed in series

with high-side FET drain.

INHIBIT 22 Disables the drive signals to the MOSFET drivers. Also serves as UVLO for system logic supply (3.3 V or

5 V). An external pull-up resistor should be connected to system-logic supply.

IOUT 1 Current out. Output voltage on this terminal is proportional to the load current as measured across the

R

ds(on)

of the high side FET . The voltage on this terminal equals 2 ×R

DS(ON)

×IOUT . In applications where

very accurate current-sensing is required, a sense resistor should be connected between the input supply

and the drain of the high-side FETs.

IOUTLO 21 Current sense low output. This is the voltage on the LOSENSE terminal when the high-side FETs are on.

A ceramic capacitor (between 0.033 µF and 0.1 µF) should be connected from IOUTLO to HISENSE to hold

the sensed voltage.

LODRV 10 Low drive enable. Normally tied to 5 V. To configure the low-side FET as a crowbar , pull LODRV low.

LOHIB 11 Low side inhibit. Connect to the junction of the high- and low-side FETs to control the anti-cross-

conduction and eliminate shoot-through current. Disabled when configured in crowbar mode.

LOSENSE 20 Low current sense. For current sensing across high-side FET s, connect to the source of the high-side FET s;

for optional current sensing scheme, connect to high-side FET drain side of current-sense resistor placed

in series with high-side FET drain.

LOWDR 13 Low drive. Output drive to synchronous rectifier FETs.

NC 23–27 No connect

OCP 3 Over current protection. Current limit trip point is set with a resistor divider between IOUT and ANAGND.

PWRGD 28 Power good. PWRGD signal goes high when output voltage is within 7% of voltage setpoint. Open-drain

output.

SLOWST 8 Slow Start (soft start). A capacitor form SLOWST to ANAGND sets the slowstart time.

Slowstart current = I

VREFB

/5

VHYST 4 Hysteresis set input. The hysteresis is set with a resistor divider from VREFB to ANAGND.

Hysteresis = 2 × (VREFB – VHYST)

V

CC

15 12-V supply. A 1-µF capacitor should be connected from V

CC

to DRVGND.

VREFB 5 Buffered reference voltage

VSENSE 6 Voltage sense Input. T o be connected from converter output voltage bus to sense and control output voltage.

It is recommended that a RC low-pass filter be connected at this pin to filter noise.

TPS5615, TPS5618, TPS5625, TPS5633

SYNCHRONOUS-BUCK HYSTERETIC REGULATOR CONTROLLER

SLVS177A – SEPTEMBER 1998 – REVISED NOVEMBER 1998

4

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

detailed description

Vref

The reference voltage section consists of a temperature-compensated bandgap reference and a resistive

divider that sets the output voltage option. The output voltage, VREF, is within 1% of the nominal setting over

the full junction temperature range of 0°C to 125°C, and a V

CC

supply voltage range of 11.4 V to 12.6 V. The

output of the reference network is indirectly brought out through a buffer to the VREFB pin. The voltage on this

pin will be within 2% of VREF . It is not recommended to drive loads with VREFB, other than setting the hysteresis

of the hysteretic comparator, because the current drawn from VREFB sets the charging current for the slowstart

capacitor. Refer to the

slowstart

section for additional information.

hysteretic comparator

The hysteretic comparator regulates the output voltage of the synchronous-buck converter. The hysteresis is

set by 2 external resistors and is centered on VREF . The 2 external resistors form a resistor divider from VREFB

to ANAGND, with the output voltage connecting to the VHYST pin. The hysteresis of the propagation delay from

the comparator inputs to the driver outputs is 250 ns (maximum). The maximum hysteresis setting is 60 mV.

R1

+

R2

V

H

2

VREFB–V

H

Where

V

H

=

desired

hysteresis

voltage

I

O(MAX)

= 0.5 µA

VHYST

TPS56xx

VREFB

R1

R2

+

2

ǒ

VREFB

*

V

H

Ǔ

Figure 1. Setting the Hysteresis Voltage

low-side driver

The low-side driver is designed to drive low-R

ds(on)

n-channel MOSFETs. The current rating of the driver is 2

A, source or sink. The bias to the low-side driver is internally connected to the DRV regulator.

high-side driver

The high-side driver is designed to drive low-R

ds(on)

n-channel MOSFETs. The current rating of the driver is 2

A, source or sink. The high-side driver can be configured either as a ground-referenced driver or as a floating

bootstrap driver. When configured as a floating driver , the bias voltage to the driver is developed from the DR V

regulator. The internal bootstrap diode, connected between the DR V and BOOT pins, is a Schottky for improved

drive efficiency. The maximum voltage that can be applied between BOOT and DRVGND is 30 V. The driver

can be referenced to ground by connecting BOOTLO to DRVGND, and connecting BOOT to either DRV or V

CC

.

deadtime control

Deadtime control prevents shoot-through current from flowing through the main power FETs during switching

transitions by actively controlling the turn-on times of the MOSFET drivers. The high-side driver is not allowed

to turn on until the gate-drive voltage to the low-side FET is below 2 V; the low-side driver is not allowed to turn

on until the voltage at the junction of the 2 FETs (Vphase) is below 2 V.

TPS5615, TPS5618, TPS5625, TPS5633

SYNCHRONOUS-BUCK HYSTERETIC REGULATOR CONTROLLER

SLVS177A – SEPTEMBER 1998 – REVISED NOVEMBER 1998

5

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

detailed description (continued)

current sensing

Current sensing is achieved by sampling and holding the voltage across the high-side power FET while the

high-side FET is on. The sampling network consists of an internal 60-Ω switch and an external ceramic hold

capacitor. Recommended value of the hold capacitor is between 0.033 µ F and 0.1 µF. The actual value should

give a time constant (60 Ω × C

H

) greater than the FET on time. Internal logic controls the turn-on and turn-off

of the sample/hold switch such that the switch does not turn on until the Vphase voltage transitions high, and

the switch turns off when the input to the high-side driver goes low . Thus sampling will occur only when the high

side FET is conducting current. The voltage on the IOUT pin equals 2 times the sensed high-side voltage. In

applications where a higher accuracy in current-sensing is required, a sense resistor can be placed in series

with the high-side FET and the voltage across the sense resistor can be sampled by the current sensing circuit.

See Figures 2 and 3.

overcurrent protection

The overcurrent protection (OCP) circuit monitors the current through the high-side FET. The overcurrent

threshold is adjustable with an external resistor divider between IOUT and ANAGND, with the divider voltage

connected to OCP. If the voltage on OCP (V

S

) exceeds 100 mV , then a fault latch is set and the output drivers

are turned off. The latch will remain set until V

CC

goes below the undervoltage lockout value. A 3-µs deglitch

timer is included for noise immunity . The OCP circuit is also designed to protect the high-side power FET against

a short-to-ground fault on the terminal common to both power FETs (Vphase).

R1

+

R2

ǒ

V

S

–0.05

Ǔ

0.05

Figure 2. OCP Using FET ON-Resistance

Figure 3. Precision OCP Using External Resistor

R1

+

R2

ǒ

V

S

–0.05

Ǔ

0.05

R2

2 * V

S

OCP

TPS56xx

R1

IOUT

IOUTLO

HISENSE

LOSENSE

HIGHDR

V

CC

V

P

C

H

V

S

R2

2 * V

S

OCP

TPS56xx

R1

IOUT

IOUTLO

HISENSE

LOSENSE

HIGHDR

V

CC

V

P

C

H

V

S

R

S

inhibit

INHIBIT is a TTL-compatible digital input used to enable the controller. When INHIBIT is low , the output drivers

are low and the slowstart capacitor is discharged. When INHIBIT goes high, the short across the slowstart

capacitor is released and normal converter operation begins. When the system-logic supply is connected to

INHIBIT, it also controls power sequencing by locking out controller operation until the system-logic supply

exceeds the input threshold voltage of the inhibit circuit. Thus the 12-V supply and the system-logic supply

(either 5 V or 3.3 V) must be above UVLO thresholds before the controller is allowed to start up. The INHIBIT

comparator start threshold is 2.1 V and the hysteresis is 100 mV.

TPS5615, TPS5618, TPS5625, TPS5633

SYNCHRONOUS-BUCK HYSTERETIC REGULATOR CONTROLLER

SLVS177A – SEPTEMBER 1998 – REVISED NOVEMBER 1998

6

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

detailed description (continued)

R2

+

2.1

R1

V

TRIP

–2.1

Where

V

TRIP

=desired V

SUPPLY

trip voltage

R2

INHIBIT

TPS56xx

R1

To Power Stage

SHUTDOWN

V

CC

Figure 4. Input Undervoltage Lockout Circuit Using INHIBIT

V

CC

undervoltage lockout (UVLO)

The undervoltage lockout circuit disables the controller while the V

CC

supply is below the 10-V start threshold

during power-up. While the controller is disabled, the output drivers will be low and the slowstart capacitor will

be shorted. When V

CC

exceeds the start threshold, the short across the slowstart capacitor is released and

normal converter operation begins. There is a 2-V hysteresis in the undervoltage lockout circuit for noise

immunity.

slowstart

The slowstart circuit controls the rate at which V

O

powers up. A capacitor is connected between SLOWSST and

ANAGND and is charged by an internal current source. The slowstart charging current is determined by the

following equation:

I

SLOWSTART

+

I(VREFB)

5

where I(VREFB) is the current flowing out of VREFB. It is recommended that no additional loads be connected

to VREFB, other than the resistor divider for setting the hysteresis voltage. The maximum current that can be

sourced by the VREFB circuit is 500 µA. The slowstart time is set by:

t

SLOWSTART

+

5

C

SLOWST

R

VREFB

where R

VREFB

is the total external resistance from VREFB to ANAGND.

power good

The power good circuit monitors for an undervoltage condition on V

O

. If V

O

is 7% below V

REF

, then PWRGD

is pulled low. PWRGD is an open-drain output.

overvoltage protection

The overvoltage protection (OVP) circuit monitors V

O

for an overvoltage condition. If V

O

is 15% above V

REF

,

then a fault latch is set and both output drivers are turned off. The latch will remain set until V

CC

goes below the

undervoltage lockout value. A 3-µs deglitch timer is included for noise immunity. Refer to the LODRV section

for information on how to protect the load against overvoltages due to a shorted fault across the high-side power

FET .

TPS5615, TPS5618, TPS5625, TPS5633

SYNCHRONOUS-BUCK HYSTERETIC REGULATOR CONTROLLER

SLVS177A – SEPTEMBER 1998 – REVISED NOVEMBER 1998

7

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

detailed description (continued)

drive regulator

The drive regulator provides drive voltage to the output drivers. The minimum drive voltage is 7 V . The minimum

short circuit current is 100 mA. Connect a 1-µF ceramic capacitor from DRV to DRVGND.

LODRV

The LODRV circuit is designed to protect the load against overvoltages that occur if the high-side FET s become

shorted. External components to sense an overvoltage condition are required to use this feature. When an

overvoltage fault occurs, LODRV is pulled low and the low-side FET will be turned on, overriding all control

signals inside the TPS56xx controller. The crowbar action will short the system-logic supply to ground through

the faulted high-side FET s and the low-side FETs. A fuse, in series with V

IN

, should be added to disconnect the

short circuit.

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

†

Supply voltage range, V

CC

(see Note 1) –0.3 to 14 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Input voltage range: BOOT to DRVGND (high-side driver ON) –0.3 to 30 V. . . . . . . . . . . . . . . . . . . . . . . . . . .

BOOT to HIGHDRV –0.3 to 15 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

BOOT to BOOTLO –0.3 to 15 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

INHIBIT, LODRV –0.3 to 7.3 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

PWRGD, OCP –0.3 to 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LOHIB, LOSENSE, IOUTLO, HISENSE –0.3 to 14 V. . . . . . . . . . . . . . . . . . . . . . . . . . . .

VSENSE –0.3 to 5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Voltage difference between ANAGND and DRVGND ±0.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Output current, VREFB 0.5 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Short circuit duration, DRV Continuous. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

Operating junction temperature range, T

J

0°C to 125°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Storage temperature range, T

stg

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

Lead temperature soldering 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: Unless otherwise specified, all voltages are with respect to ANAGND.

DISSIPATION RATING TABLE

PACKAGE

T

A

≤ 25°C

POWER RATING

DERATING FACTOR

ABOVE T

A

= 25°C

T

A

= 70°C

POWER RATING

T

A

= 85°C

POWER RATING

PWP 1150 mW 11.5 mW/°C 630 mW 460 mW

TPS5615, TPS5618, TPS5625, TPS5633

SYNCHRONOUS-BUCK HYSTERETIC REGULATOR CONTROLLER

SLVS177A – SEPTEMBER 1998 – REVISED NOVEMBER 1998

8

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

recommended operating conditions

MIN MAX UNIT

Supply voltage, V

CC

11.4 13 V

BOOT to DRVGND 0 28

BOOT to BOOTLO 0 13

Input voltage

INHIBIT, LODRV, PWRGD, OCP 0 6

V

LOHIB, LOSENSE, IOUTLO, HISENSE 0 13

VSENSE 0 4.5

Voltage dif ference between ANAGND and DRVGND 0 ±0.2 V

Output current, VREFB

†

0 0.4 mA

†

Not recommended to load VREFB other than to set hysteresis since I

VREFB

sets slowstart time.

electrical characteristics over recommended operating virtual junction temperature range,

V

CC

= 12 V, I

DRV

= 0 A (unless otherwise noted)

reference

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

TPS5615 1.485 1.515

Reference

TPS5618

1.782 1.818

VREF

Reference

voltage

TPS5625

V

CC

=

11

.

4

V

to

12

.

6

V

2.475 2.525

V

TPS5633 3.267 3.333

VREFB Output voltage I

REFB

= 50 µA VREF–2% VREF VREF+2% V

VREFB Output regulation 10 µA ≤ I

O

≤ 500 µA 2 mV

power good

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Undervoltage trip threshold 90 93 95 %VREF

Low-level output voltage, PWRGD I

O

= 5 mA 0.5 0.75 V

High-level input current, PWRGD V

PWRGD

= 6 V 1 µA

Hysteresis 10 mV

overvoltage protection

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Overvoltage trip threshold 112 115 120 %VREF

Hysteresis See Note 2 10 mV

NOTE 2: Ensured by design, not tested.

slowstart

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Charge current V

SLOWST

= 0.5 V, I

VREFB

= 65 µA 10.4 13 15.6 µA

Discharge current V

SOFTST

= 1 V 3 mA

Comparator input offset voltage 10 mV

Comparator input bias current See Note 2 10 100 nA

Hysteresis –7.5 7.5 mV

NOTE 2: Ensured by design, not tested.