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REF

REF

Load Comparator

Skip Comparator

Current Limit Comparator

P-Channel

Power MOSFET

Driver

Shoot-Through

Logic

Control

Logic

Soft Start

1 MHz

Oscillator

Comparator

S

R

N-Channel

Power MOSFET

Comparator High

Comparator Low

Comparator Low 2

Sawtooth

Generator

V

I

Undervoltage

Lockout

Bias Supply

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Comparator High

Comparator Low

Comparator Low 2

Compensation

R2

See Note

R1

EN

SW

FB

GND

Gm

DETAILED DESCRIPTION

OPERATION

TPS62200

,, TPS62201

TPS62202, TPS62203, TPS62207

TPS62204, TPS62205, TPS62208

SLVS417E – MARCH 2002 – REVISED MAY 2006

FUNCTIONAL BLOCK DIAGRAM

For the adjustable version (TPS62200) the internal feedback divider is disabled and the FB pin is directly connected

to the internal GM amplifier

The TPS6220x is a synchronous step-down converter operating with typically 1-MHz fixed frequency pulse width

modulation (PWM) at moderate to heavy load currents and in power save mode operating with pulse frequency

modulation (PFM) at light load currents.

During PWM operation the converter uses a unique fast response, voltage mode, controller scheme with input

voltage feed forward. This achieves good line and load regulation and allows the use of small ceramic input and

output capacitors. At the beginning of each clock cycle initiated by the clock signal (S), the P-channel MOSFET

switch is turned on, and the inductor current ramps up until the comparator trips and the control logic turns off

the switch. The current limit comparator also turns off the switch in case the current limit of the P-channel switch

is exceeded. Then the N-channel rectifier switch is turned on and the inductor current ramps down. The next

cycle is initiated by the clock signal again turning off the N-channel rectifier and turning on the P-channel switch.

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