Load driving circuit

Load driving circuit

  • CN 105,743,475 B
  • Filed: 12/16/2015
  • Issued: 10/09/2020
  • Est. Priority Date: 12/25/2014
  • Status: Active Grant
First Claim
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1. A load driving circuit is characterized in that,the load driving circuit includes:

  • a 1 st terminal, the 1 st terminal being connected to a power supply;

    a 2 nd terminal, the 2 nd terminal being connected to a load;

    a switching element connected between the 1 st terminal and the 2 nd terminal;

    a 1 st comparator that compares a 1 st reference voltage lower than an input voltage input to the 1 st terminal and a voltage of the 2 nd terminal to detect a load open state in which the switching element is in an off state and the 2 nd terminal is not connected to the load;

    a clamp circuit that clamps a voltage of the 2 nd terminal at a clamp voltage that is higher than the 1 st reference voltage and lower than the input voltage when in the load open state;

    a 2 nd comparator that compares a 2 nd reference voltage that is lower than the input voltage and higher than the clamp voltage with a voltage of the 2 nd terminal to detect a power source mis-connection state where the switching element is in an off state and the 2 nd terminal is connected to an output terminal of the power source;

    a capacitor having one end connected to the 2 nd terminal and the other end connected to the 3 rd terminal;

    a bootstrap circuit that generates a constant voltage from a voltage of a power supply of the 1 st terminal and supplies a charging current to the 3 rd terminal with the constant voltage; and

    a clamp voltage rise suppressing circuit that suppresses a rise in a clamp voltage of the clamp circuit based on a load open state detection signal from the 1 st comparator when the 1 st comparator detects a load open state,the clamp voltage rise suppressing circuit is constituted by a charging current stop circuit which stops a charging current flowing from the bootstrap circuit to the 3 rd terminal and the capacitor when the 1 st comparator detects a load open state,the charging current stop circuit includes a switch electrically connected between the bootstrap circuit and the 3 rd terminal, and the switch is turned off when the 1 st comparator detects a load open state.

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