US 5,475,333 A · Built-in drive power-source semiconductor device

Abstract

A built-in drive-power-source semiconductor device of low cost having a good switching characteristic and a decreased switching loss. In operation, a reference charge potential is applied to a charging IGBT by a first constant voltage diode thereby turning on the IGBT to charge a battery means. When the charge potential of the battery means reaches a prescribed level, a MOSFET is turned on by a second constant voltage diode, shortcircuiting the first constant voltage diode, causing the charging IGBT is turn off to eliminate overcharging of the batter means and maintain the potential of the battery means at a prescribed value. The semiconductor device includes a light emitting circuit for emitting light in response to an input control signal, a photo voltage generating circuit for charging the battery portion with at least a portion of the photo voltage generated in response to light from the light emitting circuit and, a disabling circuit for disabling the output IGBT when the battery means has not yet reached a sufficient level of charge potential.

Claims36

Dependent claims

A built-in drive-power-source semiconductor device comprising:

output switch means for switching power between first and second terminals of a circuit external to said semiconductor device;
output control means for controlling said output switch means in response to an input control signal;
battery means for supplying drive power to said output control means;
charging means for charging said battery means from said circuit external to said semiconductor device, said charging means including:
constant voltage output means, connected to said external circuit, for providing a charge reference potential,
charge switch means for conducting charge current to said battery means from said external circuit in response to said charge reference potential,
means for generating a predetermined charge potential level, and
charge termination means, coupled to said means for generating said predetermined charge potential level, for turning off said charge switch means when a charge potential of said battery means reaches said predetermined charge potential level.

5 more elements

Dependencies are inferred from the claim text.

Built-in drive power-source semiconductor device

Life of this patent

Built-in drive power-source semiconductor device

Life of this patent

Abstract

Claims36