TPS40000, TPS40001

TPS40002, TPS40003

TPS40004, TPS40005

SLUS507D − JANUARY 2002 − REVISED NOVEMBER 2005

8

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APPLICATION INFORMATION

The TPS4000x series of synchronous buck controller devices is optimized for high-efficiency dc-to-dc

conversion in non-isolated distributed power systems. A typical application circuit is shown in Figure 1.

The TPS40004 and TPS40005 are the controllers of choice for most general purpose synchronous buck

designs. Each operates in two quadrant mode (i.e. source or sink current) full time. This choice provides the

best performance for output voltage load transient response over the widest load current range.

The TPS40001 and TPS40003 add an additional feature: They operate in single quadrant mode (i.e. source

current only) during converter startup, and then when the converter has reached the regulation point, the

controllers change to operate in two quadrant mode. This is useful for applications that have outputs pre-biased

at some voltage before the controller is enabled. When the TPS40001 or TPS40003 is enabled, it does not sink

current during startup and therefore does not pull current from the pre-biased voltage supply.

The TPS40000 and TPS40002 operate in single quadrant mode (source current only) full time, allowing the

paralleling of converters. Single quadrant operation ensures one converter does pull current from a paralleled

converter. A converter using one of these controllers emulates a non-synchronous buck converter at light loads.

When current in the output inductor attempts to reverse, an internal zero-current detection circuit turns OFF the

synchronous rectifier and causes the current flow in the inductor to become discontinuous. At average load

currents greater than the peak amplitude of the inductor ripple current, the converter returns to operation as a

synchronous buck converter to maximize efficiency.

UDG−02013

10

µF

20 k

W

100

µF

7.68 k

Ω

470

µF 10 µF 15.7 kΩ

243

Ω

10 k

Ω

VOUT 1.8 V

10 A

1.0

µH

Si4836DY

IHLP5050CE−01

Si4836DY

5

8

7

10

9

1

2

3

ILIM

FB

COMP

GND

HDRV

SW

VDD

LDRV

3.6 nF

4

4.7 nF

SS/SD

6

BOOT

100 pF

TPS40001

100 nF

3.3 nF

3.3

Ω

VDD

3.0 V to 5.5 V

Figure 1. Typical Application Circuit