FB

VIN

VCC

REGULATOR

DRIVER

HB

ADAPTIVE

TIMER

EN

UVLO

UVLO

ERROR

AMP

DIS

COMP

CLK

S

R

Q

Q

OSCILLATOR

AGND

CLK

CSG

RAMP GENERATOR

+

SLEEP

MODE

SHUTDOWN

PWM

CURRENT

LIMIT

RAMP

SS

VIN

10 x RS V/A

5 2A

1V

10 2A

CS

DRIVER

PGND

LO

VOUT

HO

SW

1

2

3

4

5

14

6

15

10

13

12

20

19

18

+

-

4.5V

17

HICCUP FAULT TIMER

256 CLOCK CYCLES

UVLO

LOGIC

STANDBY

UVLO

7

8

9

16

VCCX

RT

A =10

VCC

DEMB

11

TRACK

SAMPLE

and

HOLD

CLK

DIODE

EMULATION

CONTROL

SS

SW

THERMAL

SHUTDOWN

3V

VCCX

EN

SYNC

1.215 V

CCOMP

RCOMP

CHF

1

0.5V

RS

CSNUB

VOUT

R SNUB

COUT

Q2

Q1

L1

RFB1

RFB2

IR

D1

C VCC

CVCCX

VIN

CHB

RT/SYNC

CRAMP

CSYNC

1.215V

7. 4 V

LM 5116

REN

RUV2

RUV1

CIN

CFT

CSS

VIN

6V -100V

D2

IR = 52A

( VIN - VOUT ) + 252A

V x

/

.6V

LM5116-HT

SLVSBS8B – OCTOBER 2013 – REVISED JANUARY 2014

www.ti.com

Block Diagram and Typical Application Circuit

Figure 2. Typical Application

Detailed Operating Description

The LM5116 high voltage switching regulator features all of the functions necessary to implement an efficient

high voltage buck regulator using a minimum of external components. This easy to use regulator integrates high-

side and low-side MOSFET drivers capable of supplying peak currents of 2 A. The regulator control method is

based on current mode control utilizing an emulated current ramp. Emulated peak current mode control provides

inherent line feed-forward, cycle by cycle current limiting and ease of loop compensation. The use of an

emulated control ramp reduces noise sensitivity of the pulse-width modulation circuit, allowing reliable processing

of the very small duty cycles necessary in high input voltage applications. The operating frequency is user

programmable from 50 kHz to 1 MHz. An oscillator/synchronization pin allows the operating frequency to be set

by a single resistor or synchronized to an external clock. Fault protection features include current limiting, thermal

shutdown and remote shutdown capability. An under-voltage lockout input allows regulator shutdown when the

input voltage is below a user selected threshold, and an enable function will put the regulator into an extremely

low current shutdown via the enable input.

High Voltage Start-Up Regulator

The LM5116 contains a dual mode internal high voltage startup regulator that provides the VCC bias supply for

the PWM controller and a boot-strap gate drive for the high-side buck MOSFET. The input pin (VIN) can be

connected directly to an input voltage source as high as 100 V. For input voltages below 10.6 V, a low dropout

switch connects VCC directly to VIN. In this supply range, VCC is approximately equal to VIN. For VIN voltages

greater than 10.6 V, the low dropout switch is disabled and the VCC regulator is enabled to maintain VCC at

approximately 7.4 V. The wide operating range of 6 V to 80 V is achieved through the use of this dual mode

regulator.

12

Submit Documentation Feedback

Copyright © 2013–2014, Texas Instruments Incorporated

Product Folder Links: LM5116-HT