Datasheet

TPS62660, TPS62665

SLVS871C –FEBRUARY 2010– REVISED JULY 2011

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OUTPUT CAPACITOR DISCHARGE

The TPS6266x device can actively discharge the output capacitor when it turns off. The integrated discharge

resistor has a typical resistance of 15 Ω. The required time to discharge the output capacitor at the output node

depends on load current and the output capacitance value.

UNDERVOLTAGE LOCKOUT

The undervoltage lockout circuit prevents the device from misoperation at low input voltages. It prevents the

converter from turning on the switch or rectifier MOSFET under undefined conditions. The TPS6266x device

have a UVLO threshold set to 2.05V (typical). Fully functional operation is permitted down to 2.1V input voltage.

SHORT-CIRCUIT PROTECTION

The TPS6266x integrates a P-channel MOSFET current limit to protect the device against heavy load or short

circuits. When the current in the P-channel MOSFET reaches its current limit, the P-channel MOSFET is turned

off and the N-channel MOSFET is turned on. The regulator continues to limit the current on a cycle-by-cycle

basis.

As soon as the output voltage falls below ca. 0.4V, the converter current limit is reduced to half of the nominal

value. Because the short-circuit protection is enabled during start-up, the device does not deliver more than half

of its nominal current limit until the output voltage exceeds approximately 0.5V. This needs to be considered

when a load acting as a current sink is connected to the output of the converter.

THERMAL SHUTDOWN

As soon as the junction temperature, T

, exceeds typically 140°C, the device goes into thermal shutdown. In this

mode, the P- and N-channel MOSFETs are turned off. The device continues its operation when the junction

temperature again falls below typically 130°C.