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SWITCH DRIVE CIRCUIT

  • US 20180034368A1
  • Filed: 07/26/2016
  • Published: 02/01/2018
  • Est. Priority Date: 07/26/2016
  • Status: Active Grant
First Claim
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1. A switch drive circuit which operates a load by alternately performing switching of a high-side switch placed in a high side and a low-side switch placed in a low side, the switch drive circuit comprising:

  • a high-side power supply section which is a power supply for a high-side circuit;

    a latch circuit which receives power supplied from the high-side power supply section and which latches a logical level of a high-side switching signal at the time of performing switching of the high-side switch;

    a high-side driver which receives power supplied from the high-side power supply section and which drives the high-side switch by the high-side switching signal outputted from the latch circuit;

    a low-side driver which receives power supplied from a power supply for a low-side circuit and which drives the low-side switch by a low-side switching signal; and

    a high-side switch control circuit which sets, at the time of stopping the switching of the high-side switch, a stop established state in which the logical level of the high-side switching signal is fixed at a stop logic level needed for stopping the switching and which releases the stop established state at the time of performing the switching of the high-side switch,wherein;

    the high-side switch control circuit includes a constant-current source which generates a reference current, a resistor, and a three-terminal switch;

    an input end of the constant-current source and a first input end of the three-terminal switch are connected to a first potential side of the high-side power supply section and one end of the resistor is connected to a second potential side of the high-side power supply section;

    another end of the resistor is connected to an output end of the constant-current source and a second input end of the three-terminal switch and an output end of the three-terminal switch is connected to an input end of the latch circuit; and

    the stop established state is set or released in the latch circuit by cutting off or passing the reference current and controlling switching of the three-terminal switch.

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