NORMAL MODE AND SKIP MODE OPERATION

t

t

t

t

GateWaveform

OfQ1 Transistor

Loadcurrent

Noload

Startup

Waveform

SkipModeat

NoLoadCondition

NormalModeat

50 mA LoadCurrent

SkipModeat

NoLoadCondition

QuiescentCurrent

90 A

m

4.7mA

50mA

5V+0.1V

5V

TPS60151

Figure 24. Normal Mode and Skip Mode Operation

The TPS60151 has skip mode operation as shown in Figure 24. The TPS60151 enters skip mode if the output

voltage reaches 5V+0.1V and the load current is below 8mA (typ). In Skip Mode, the TPS60151 disables the

oscillator and decreases the pre-bias current of the output stage to reduce the power consumption. Once the

output voltage dips below threshold voltage, 5V+0.1V, the TPS60151 begins switching to increase output voltage

until the output reaches 5V+0.1V. When the output voltage dips below 5V, the TPS60151 returns to normal PWM

mode; thereby re-enabling the oscillator and increasing the pre_bias current of the output stage to supply output

current.

The skip threshold voltage and current depend on input voltage and output current conditions.

Copyright © 2009, Texas Instruments Incorporated

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