OUTxshortedwhiledriving6.7 A load

Outputcapacitanceis47 F

m

620mV

675mV

Time-2ms/div

GAT1x,

10V/div

MONx,

1V/div

OUTx,

10V/div

OUTxshortedwhiledriving6.7 A load

Outputcapacitanceis47 F

m

620mV

Time-1 s/div

m

GAT1x,

10V/div

MONx,

1V/div

OUTx,

10V/div

GAT1x,

2V/div

OUTxstartingintoshortcircuit

675mV

MONx,

0.5V/div

OUTx,

20mV/div

2.9V

Time-1ms/div

GAT1x,

10V/div

OUTxoverloadedwhilesupplying6.7 A

970mV

MONx,

0.5V/div

OUTx,

10V/div

675mV

Time-1ms/div

TPS2456

www.ti.com

SLVSA78A – MARCH 2010 – REVISED MARCH 2010

TYPICAL CHARACTERISTICS (continued)

Figure 13. Short Circuit Under Full Load (6.7 A) Wide

Figure 14. Short Circuit Under Full Load (6.7 A) Zoom View

Figure 15. Startup into Short Circuit

Figure 16. Overloaded while Supplying 6.7 A

SYSTEM OPERATION

INTRODUCTION

The TPS2456 controls two 12-V channels, or power paths. The channels can draw from a single common

supply, or from two independent supplies. The following sections describe the TPS2456 operation and provide

guidance for designing systems around this device.

CONTROL LOGIC AND POWER-ON RESET

The TPS2456 circuitry draws bias power from any of the INx or OUTx pins through an internal preregulator that

generates VINT. A bypass capacitor from VINT to ground provides decoupling and output filtering for the internal

circuits. Bias supply ORing allows the internal circuitry to function regardless of which channels receive power or

are in a faulted state. The four external MOSFET drive pins (GAT1A, GAT1B, GAT2A, and GAT2B) are held low

during startup to ensure that the channels remain off. When the voltage on the internal VINT rail exceeds

approximately 1 V, the power-on reset (POR) circuit initializes the TPS2456 and allows normal operation.

Copyright © 2010, Texas Instruments Incorporated

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Product Folder Link(s): TPS2456