Sales Information

Phone:(425) 353-3010

Fax: (425) 353-4030

SVFA0515S - 4.0

E-mail: vptsales@vptpower.com

Web: www.vptpower.com

Page 7

SVFA0515S Series

6.3 PROTECTION FEATURES

6.3.1 Input Undervoltage Lockout

The SVFA0515S Series provides input undervoltage lockout protection. For input voltages below the turn-on voltage, the converter will

remain off. When the input voltage exceeds the turn-on voltage, the converter will start. For input voltages below the operating range of

the converter but above the UVLO turn-off voltage, the converter may reach its maximum duty cycle and the output may drop out of

regulation.

6.3.2 Output Soft-Start

The SVFA0515S Series utilizes an output soft-start function to ramp the output in a controlled manner, eliminating output voltage

overshoot and limiting inrush current at turn on. A voltage mode soft-start ensures the output waveform remains consistent regardless

of changes in the load current. The output rise time is approximately 3 ms. The soft-start function is active whether the module is

turned on with an application of input voltage or from release of the INH pin. The turn-on delay time is specified from the application of

input voltage (or release of INH pin) until the output reaches 90% of its final value.

6.3.3 Output Short Circuit Protection

The SVFA0515S Series provides output short circuit protection. When a sustained high peak current is detected, the converter will shut

down and enter a hiccup mode. After a delay, the converter will attempt a soft-start. This sequence will continue until the fault is

removed, allowing the converter to soft-start and resume normal operation.

6.4 THERMAL CONSIDERATIONS

The SVFA0515S is rated for full power operation at 125 °C. Operation above 125 °C is allowed at reduced power. Specifically, the

output power should be derated linearly from full power at 125 °C to half power at 130 °C and to zero power at 135 °C. The operating

temperature of the converter is specified on the baseplate of the converter. The converter is designed to be conduction-cooled, with the

baseplate mounted to a heat sink, chassis, PCB or other thermal surface. The internal power dissipating components are mounted to

the baseplate of the converter and all heat flow is through the baseplate. The lid of the converter does not provide a good thermal path.

The hybrid DC-DC converter contains many semiconductor components. The maximum temperature rise from junction to case is 11 °C

at full load.