t

4.5

C

BP5

8

1.0

0.7

EN

BP5

SS

VOUT

PGOOD

t -Time

BP5

BP5

BP5

1

2

3

4

4-Phase

Operation

1

2

3

4

3-Phase

Operation

2-Phase

Operation

1

2

3

4

TPS40090

TPS40091

www.ti.com

SLUS578B

– OCTOBER 2003 – REVISED MAY 2006

SETTING CONTROLLER CONFIGURATION

By default, the controller operates at four-phase configuration. The alternate number of active phases is

programmed by connecting unused PWM outputs to BP5. (See Figure 1) For example, for three-phase

operation, the unused fourth phase output, PWM4, should be connected to BP5. For two-phase operation, the

second, PWM2, and the fourth, PWM4, outputs should be connected to BP5.

POWER UP

Capacitors connected to the BP5 pin and the soft-start pin set the power-up time. When EN is high, the capacitor

connected to the BP5 pin gets charged by the internal LDO as shown in Figure 2.

(1)

Figure 1. Programming Controller Configuration

Figure 2. Power-Up Waveforms

Copyright

© 2003–2006, Texas Instruments Incorporated

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