Load drive circuit
AssigneeOki Semiconductor Co., Ltd.
InventorsNorihiro KAWAGISHI, Kazuyoshi ASAKAWA
Life of this patent
Estimating the term…
Abstract
A load drive circuit which can operate at high speed with low consumption current while performing the gate-to-source over voltage protection for its load driving field-effect transistor. A Zener function device is connected between the gate and the source of the load driving field-effect transistor, and an on/off-switch circuit to supply either on-potential or off-potential to the gate of the field effect transistor is provided. The current flowing through the Zener function device when the load driving field-effect transistor is conductive is limited by the on/off-switch circuit.
Claims18
A load drive circuit comprising:
- a field effect transistor having a source connected to a power supply voltage or a reference potential and a drain;
- an output terminal connected to the drain of said field effect transistor;
- a Zener function device connected between a gate and the source of said field effect transistor;
- and
- an on/off-switch circuit connected between said power supply voltage and said reference potential to give either on-potential or off-potential to the gate of said field effect transistor,
- wherein said on/off-switch circuit comprises an off-switch transistor having a source and a drain connected respectively to input and output terminals of said Zener function device;
- a series circuit of a first on-switch transistor and a current source, which circuit is connected between said gate and one of said power supply voltage and said reference potential;
- and a second on-switch transistor connected in parallel with said series circuit.
Dependencies are inferred from the claim text.