TI 3-A DUAL NON-SYNCHRONOUS CONVERTER WITH INTEGRATED HIGH-SIDE MOSFET

The TPS54383 and TPS54386 are dual output, non-synchronous buck converters capable of supporting 3-A output applications that operate from a 4.5-V to 28-V input supply voltage, and require output voltages between 0.8 V and 90% of the input voltage.

　　With an internally-determined operating frequency, soft start time, and control loop compensation, these converters provide many features with a minimum of external components. Channel 1 overcurrent protection is set at 4.5 A, while Channel 2 overcurrent protection level is selected by connecting a pin to ground, to BP, or left floating. The setting levels are used to allow for scaling of external components for applications that do not need the full load capability of both outputs.

　　The outputs may be enabled independently, or may be configured to allow either ratiometric or sequential startup sequencing. Additionally, the two outputs may be powered from different sources.

主要特性:

4.5-V to 28-V Input Range

Output Voltage Range 0.8 V to 90% of Input Voltage

Output Current Up to 3 A

Two Fixed Switching Frequency Versions:

TPS54383: 300 kHz

TPS54386: 600 kHz

Three Selectable Levels of Overcurrent Protection (Output 2)

0.8-V 1.5% Voltage Reference

2.1-ms Internal Soft Start

Dual PWM Outputs 180° Out-of-Phase

Ratiometric or Sequential Startup Modes Selectable by a Single Pin

85-mInternal High-Side MOSFETs

Current Mode Control

Internal Compensation (See Page 16)

Pulse-by-Pulse Overcurrent Protection

Thermal Shutdown Protection at +148°C

14-Pin PowerPAD™ HTSSOP package

应用:

Set Top Box

Digital TV

Power for DSP

Consumer Electronics

图1. TPS54383/6方框图。

设计案例:

案例1: 12-V 到5-V 和3.3-V转换器的详情设计

　　The following example illustrates a design process and component selection for a 12-V to 5-V and 3.3-V dual non-synchronous buck regulator using the TPS54383 converter.

　　表1.设计案例所用元件清单(BOM)

案例2: 24-V到12-V 以及24-V 到5-V转换器详细设计

　　For a higher input voltage, both a snubber and bootstrap resistors are added to reduce ringing on the switch node and a 30 V schottky diode is selected. A higher resistance feedback network is chosen for the 12 V output to reduce the feedback current.

案例3: 5-V 到3.3V 以及5-V 到1.2 V详细设计

　　For a low input voltage application, the TPS54386 is selected for reduced size and all ceramic output capacitors are used. 22-F input capacitors are selected to reduce input ripple and lead capacitors are placed in the feedback to boost phase margin.