1 Features

1• Low-Side Gate Driver With Body-Diode

Conduction Sensing

• Gate Turnoff Edge Body-Diode Conduction

Reporting synchronous•

Gate Turnon Edge Delay Optimization high•

Works Together With the Dead-Time

Compensation (DTC) Module in the UCD3138A

Family of Digital Power Controllers:

– Automatic or Manual Dead-Time Adjustment of

Gate Turnon and Turnoff Edges

– Negative Current Protection

• -150-mV Body-Diode Conduction Sensing

Threshold

• Able to Sense Body Diode Conduction Times as

Low as 10 ns

• 4-A Peak-Source and 6-A Peak-Sink Drive

Current

• Fast Propagation Delays (14-ns Typical)

• Fast Rise and Fall Times (5-ns Typical)

• Up to 2-MHz Operating Frequency

• 4.5-V to 18-V Supply Range

• Rail-to-Rail Drive Capability

• VCC Undervoltage Lockout (UVLO)

• 6-Pin 3-mm × 3-mm WSON-6 Package

2 Applications

• LLC Converters

• Hard Switching Full-Bridge Converters

• Digital Power-Control Applications

3 Description

The UCD7138 device is a 4-A and 6-A single-channel

MOSFET driver with body-diode conduction sensing

and reporting and is a high performance driver that

allows the Texas Instruments UCD3138A digital

PWM controller to achieve advanced synchronous•

rectification (SR) control. The device contains a high•

speed gate driver, a body-diode conduction-sensing

circuit, and a turnon delay optimization circuit. The

device is suitable for high-power, high-efficiency isolated converter applications where SR dead-time

optimization is desired.

The UCD7138 device offers asymmetrical rail-to-rail

4-A source and 6-A sink peak-current drive capability.

The short propagation delay and fast rise and fall

time allows efficient operation at high frequencies. An

internal high-speed comparator with a –150-mV

threshold detects the body-diode conduction and reports the information to the UCD3138A digital-

power controller. The UCD7138 device is capable of

sensing body-diode conduction time as low as 10 ns.

The SR turnon edge is optimized by the UCD7138

device. The SR turnoff edge is optimized by the UCD3138A digital-power controller which analyzes

the body-diode conduction information reported by

the UCD7138 DTC pin.

The benefits of the chipset include maximizing

system efficiency by minimizing body-diode

conduction time, robust and fast negative-current

protection, and a simple interface.