Gate driver circuit and motor driving device
AssigneeRohm Co., Ltd.
InventorHisashi SUGIE
Life of this patent
Estimating the term…
Abstract
An under voltage detection circuit compares a potential difference between a bootstrap line and an output line with a threshold voltage. A voltage line generates a voltage lower by a predetermined voltage than the bootstrap line. A current mirror circuit is connected to the bootstrap line. A first resistor and a MOS diode are connected in series between an input node of the current mirror circuit and the output line. A second resistor is connected between an output node of the current mirror circuit and the voltage line. A comparator compares a voltage drop across the second resistor with a threshold voltage.
Claims7
A gate driver circuit, driving an N-type high-side transistor, comprising:
- an output line to be connected to a source of the high-side transistor;
- a bootstrap line to be connected to the high-side transistor via a bootstrap capacitor;
- a voltage source applying a constant voltage to the bootstrap line;
- an under voltage detection circuit comparing a potential difference between the bootstrap line and the output line with a threshold voltage;
- and
- a voltage line generating a voltage lower by a predetermined voltage than the bootstrap line,
- wherein the under voltage detection circuit includes:
- a current mirror circuit connected to the bootstrap line;
- a first resistor and at least one MOS (metal oxide semiconductor) diode, which is a MOS transistor with its gate and drain connected together, connected in series between an input node of the current mirror circuit and the output line;
- a second resistor connected between an output node of the current mirror circuit and the voltage line;
- and
- a comparator comparing a voltage drop across the second resistor with a threshold voltage.
Dependencies are inferred from the claim text.