PM6652 datasheet(38/53 Pages) STMICROELECTRONICS

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Device description

PM6652

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Doc ID 16867 Rev 5

the external MOSFET or the inductor, allows the controller to monitor the thermal status of

the power components (see

Figure 40).

In applications where this function is not required (in render core supply, for example) the

THERM pin must be connected to 5 V and VRTT# can be left floating.

Figure 40.

Voltage regulator thermal throttling

8.10.4

Overvoltage protection

The PM6652 can detect two kinds of VOUT overvoltage:

●

Fixed 1.55 V overvoltage threshold

●

Variable +200 mV overvoltage threshold, referred to VDAC reference voltage.

Both overvoltage protections are latched, so a COREON or SVCC toggle is required in

order to restart the device.

If the fixed overvoltage threshold is reached, the high-side MOSFET is immediately turned

off and the output capacitor is sharply discharged by turning on the low-side MOSFET. This

fault protection is always active.

When a variable VOUT overvoltage is detected, both high-side and low-side external

MOSFETs are turned off and the output capacitor soft-discharge is performed. The internal

discharge MOSFET is turned on until VOUT is lower than about 100 mV, then the low-side

MOSFET is turned on (see

Figure 20 on page 22). This fault detection is masked during VID

transitions and, during soft-start, until the power good signal is released.

8.10.5

Undervoltage protection

If the switching voltage regulator output falls below -300 mV, referred to VDAC programmed

voltage, the latched undervoltage fault is detected and the output capacitor soft-discharge is

performed. The internal discharge MOSFET is turned on until VCC_GFX is lower than about

100 mV, then the low-side MOSFET is turned on (see

Figure 21). This fault detection is

masked during VID transitions and, during soft-start, until the power good signal is released.

The undervoltage protection can't be detected if the programmed VDAC voltage is lower than

300 mV.

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