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Preliminary data sheet

Rev. 02 — 2 March 2005

5 of 21

Philips Semiconductors

PIP212-12M

DC-to-DC converter powertrain

7.3 Boost switch

The gate drive to the upper MOSFET is provided by a bootstrap capacitor (typically

100 nF) that is placed between the CBP and CBN pins. This capacitor is charged via an

will be switched according to PWM input once the boost capacitor voltage is above 4.3 V.

When ever the voltage is below 2.7 V, the upper MOSFET will remain off.

PIP212-12M, an external power supply of between 5 V and 12 V should be connected to

this pin. The optimum value for this voltage is dependent on the application but in the

7.5 3-state function

If the input to VI from the PWM controller becomes high impedance, then the VI input is

driven to 2.5 V by an internal voltage divider. A voltage on the VI pin that is in-between the

turned off. Normal operation commences once the VI input is outside this window for

7.6 Automatic Dead-time Reduction (ADR)

Protection against cross-conduction (shoot-through) is achieved via the insertion of a

delay (or dead-time) between the switching off of one MOSFET and the switching on of

the other MOSFET. The automatic dead-time reduction feature continuously monitors the

body diode of the lower MOSFET adjusting the dead-time to minimize body diode

conduction. This reduces power loss in both the upper and lower MOSFETs due to the

reduction in body diode conduction and reverse recovery charge. The lower power

dissipation leads to higher system efficiency and enables higher frequency operation.

Table 3:

VDDG_EN

Open circuit

connection to external supply required