UDG-11113

COMP2

FB2

EN2/SS2/GSNS

ILIM2/VSNS

DIFFO

BP6

+

R

R

R

R

L

O

A

D

VSNS

GSNS

Power Stage

+

FB1

COMP1

COMP1

VREF

TPS40322

www.ti.com

SLUSAF8

– JUNE 2011

Multi-Phase Mode and Current Sharing Loop

The TPS40322 can be configured to operate in single-output multi-phase mode for high-current applications.

With proper selection of the external MOSFETs, this device can support up to 50-A of load current in a

multi-phase configuration. As shown in Figure 18, to configure TPS40322 as multi-phase mode, FB2 is tied to

BP6. In this mode, COMP1 must be connected to COMP2 to ensure current sharing between the two phases.

For high-current applications, the remote sense amplifier is used to compensate for the parasitic offset to provide

an accurate output voltage. The EN2/SS2 and ILIM2 pins are designed for multiple functions. They are used as

VSNS and GSNS for remote sensing in a multi-phase mode. DIFFO, which is the output of the remote sensing

amplifier, is connected to the resistor divider of the feedback network.

Figure 18. Multi-phase Mode Configuration

When the device operates in multi-phase mode, a current sharing loop as shown in Figure 19 is designed to

maintain the current balance between phases. Both phases share the same comparator voltage (COMP1). The

sensed current in each phase is compared first in a current share block, then an error current and fed into

COMP. The resulted error voltage is compared with the voltage ramp to generate the PWM pulse.

Copyright

© 2011, Texas Instruments Incorporated

15