COMP

Network

GND

PH

BOOT

VIN

RT/CLK

SS

nRST

DELAY

VREG

IGN_EN

Buck Reg

Control

3.3V

Linear

Regulator

Control

Voltage Supervisor with

Reset delay

1.2V

3.3V

5V

3.3VSENSE

3.3VDRIVE

Wake Up

Error Amp

+

-

Ref

Internal Reg

BOOT_LDO

EN

OR

VREG

1.2VSENSE

1.2VDRIVE

VIN_D

2

4

9

5

8

20

6

12

21

23

16

17

10

18

19

VSENSE

COMP

15

22

14

1

3

+

-

0.8V

Regulator

Control

+

-

0.8V

1.2V Linear

Regulator

Control

+

-

0.8V

PGND

24

-

+

BG Ref

TPS65300-Q1

www.ti.com

SLVSBB6B – MARCH 2012 – REVISED APRIL 2012

INTERNAL FUNCTIONAL BLOCKS

Figure 17. Internal Functional Blocks

PIN FUNCTIONS

Buck Supply, VIN_D

This is an input power source for the internal high-side MOSFET of the switch-mode power supply.

Phase Node for Buck Regulator, PH

This terminal provides the floating voltage reference for the internal drive circuitry.

Bootstrap, BOOT

The ceramic capacitor on this pin acts a as a voltage supply for the internal high-side MOSFET gate-drive

circuitry. The capacitor connects between the BOOT and PH terminals. Operating with a duty cycle of 100%

automatically reduces the duty cycle to approximately 95% on every fifth cycle to allow this capacitor to recharge.

Voltage-Sense Node, VSENSE

An internal resistor between VREG and this pin and another internal resistor between this pin and ground form

the voltage-sense network. This terminal is the inverting input for the error amplifier of the control loop. This input

is compared to an internal reference of 2 V for the control circuitry.

Copyright © 2012, Texas Instruments Incorporated

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