VCC

VCC

Regulator

IADJ

COFF

20 µA

1.0 V

Control

Logic

SW

Boot

UVLO

100 µA

VIN

CSN

+

R

R

DRN

+

+

2.4 V

10 R

T

Thermal

Shutdown

T

Internal

N-channel FET

Thermal

Shutdown

PWM

5

NŸ

+

1.0 V

BOOT

PWM

GND

+

250-µs (max)

off-time

Gate

LEB

Gate

5 mA

9

TPS92515, TPS92515-Q1, TPS92515HV, TPS92515HV-Q1

www.ti.com

SLUSBZ6A – APRIL 2016 – REVISED AUGUST 2016

Product Folder Links: TPS92515 TPS92515-Q1 TPS92515HV TPS92515HV-Q1

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Copyright © 2016, Texas Instruments Incorporated

8 Detailed Description

8.1 Overview

The TPS92515 is an internal N-channel MOSFET (monolithic NFET) hysteric control, buck regulator. Hysteretic

operation allows a high control bandwidth and is ideal for shunt FET and LED matrix applications (series LED

switched network). The high-side differential current sense with low adjustable threshold voltage via a 10:1

divider, provides an excellent method for regulating output current while maintaining high system efficiency. The

device uses a controlled OFF-time (COFT) architecture to allow the converter to operate in both continuous

conduction mode (CCM) and discontinuous conduction mode (DCM) with no external control loop compensation,

and provides an inherent cycle-by-cycle current limit.

The adjustable current sense threshold provides the capability for analog dimming the LED current over the full

range and the PWM dimming input allows for high-frequency PWM dimming control requiring no external

components. Configuration options allow for easy implementation of external shunt FET dimming. See also the

OFF-Timer, Shunt FET Dimming or Shunted Output Condition section.

The device does not internally limit the maximum attainable average LED current. It does have a thermal limit

based on the maximum junction temperature. The maximum junction temperature is a function of the system

operating points (efficiency, ambient temperature, thermal management), component choices, and switching

frequency. This functionality allows the device to provide constant currents up to 1 A in a wide variety of

applications and up to 2 A in a smaller sub-set of applications. This simple regulator contains all the features

necessary to implement a high-efficiency, versatile, high-performance LED driver.

8.2 Functional Block Diagram