VOUT

VOUT_NORM

¨9=1.012 x VOUT_NORM

t

PFM at light load

PWM at medium to

heavy load

11

TPS61230A

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SLVSCZ5A – JULY 2016 – REVISED AUGUST 2016

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8.4 Device Functional Modes

The TPS61230A has two operation modes, as shown in Table 2.

Table 2. Operation Mode Description

MODE

DESCRIPTION

CONDITION

PWM

Boost in normal switching operation

Heavy load

PFM

Boost in power save operation

Light load

8.4.1 PWM Mode

The TPS61230A typically operates at a quasi-constant 1.15 MHz frequency pulse width modulation (PWM) at

moderate to heavy load currents.

8.4.2 PFM Mode

The device integrates a power save mode with the pulse frequency modulation (PFM) to improve the efficiency at

the light load. In the PFM mode, the device starts to switch when the output voltage trips below a set threshold

voltage. When the output voltage ramping over the PFM threshold, the device stops switching. The DC output

voltage in PFM mode rises above the nominal output voltage in PWM mode by 1.2%.

Figure 14. Output Voltage in PFM / PWM Mode