Electronic circuit unit and battery pack
An electronic circuit unit includes a trigger circuit and a circuit module. The trigger circuit includes a semiconductor switching element configured to output a switching pulse signal in response to an external trigger signal, a load resistor for the semiconductor switching element, a one-shot pulse circuit configured to convert the switching pulse signal into a one-shot pulse with a predetermined pulse width, and a forcible-reset circuit connected to an input side of the semiconductor switching element. The one-shot pulse circuit includes a coupling capacitor connected to an input side of the semiconductor switching element and a charging resistor for the coupling capacitor. The pulse width of the one-shot pulse is determined by a time constant of the coupling capacitor and the charging resistor. The forcible-reset circuit is configured to temporarily input an on-voltage to the semiconductor switching element so as to forcibly switch the circuit module to the operating mode.
1. An electronic circuit unit comprising:
a trigger circuit configured to output a switching pulse signal in response to an external trigger signal provided to an external input terminal; and
a circuit module including a start-up terminal, the circuit module is configured to operate in an operating mode and a power-saving mode which are switched in response to the switching pulse signal from the trigger circuit to the start-up terminal, wherein
the trigger circuit includes:
a semiconductor switching element configured to output the switching pulse signal to the start-up terminal in response to the external trigger signal;
a load resistor for the semiconductor switching element;
a one-shot pulse circuit configured to convert the switching pulse signal to be input to the start-up terminal into a one-shot pulse with a predetermined pulse width; and
a forcible-reset circuit connected to an input side of the semiconductor switching element, the forcible-reset circuit being configured to temporarily turn on the semiconductor switching element,
the start-up terminal is connected to a node connected to the semiconductor switching element and the load resistor,
the one-shot pulse circuit includes:
a first coupling capacitor connected to the input side of the semiconductor switching element; and
a first charging resistor for the first coupling capacitor,
the predetermined pulse width of the one-shot pulse is determined by a time constant of the first coupling capacitor and the first charging resistor, and
the forcible-reset circuit is configured to temporarily input an on-voltage to the semiconductor switching element so as to forcibly switch the circuit module to the operating mode.
2. The electronic circuit unit according to claim 1 , wherein
the forcible-reset circuit includes:
a series circuit including a second coupling capacitor and a second charging resistor; and
a reset terminal connected to an input side of the second coupling capacitor, and
the forcible-reset circuit is configured to temporarily turn on the semiconductor switching element in response to a forcible-reset signal input to the reset terminal.
3. The electronic circuit unit according to claim 1 , wherein
the forcible-reset circuit includes:
a series circuit including a second coupling capacitor and a second charging resistor; and
a short-circuiting switch connected to an input side of the second coupling capacitor of the forcible-reset circuit, and
the short-circuiting switch is configured to, upon being turned on, connect the input side of the second coupling capacitor to a ground line so as to temporarily turn on the semiconductor switching element.
4. The electronic circuit unit according to claim 1 , wherein the time constant is determined by a capacitance of the first coupling capacitor and a resistance of the first charging resistor such that the predetermined pulse width of the one-shot pulse is equal to or longer than 1 msec.
5. The electronic circuit unit according to claim 1 , wherein the semiconductor switching element is a field-effect transistor (FET).
6. The electronic circuit unit according to claim 1 , wherein
the first charging resistor comprises:
a second charging resistor connected between the input side of the semiconductor switching element and the first coupling capacitor; and
a third charging resistor connected between the input side of the semiconductor switching element and a power line, and
the first coupling capacitor is configured to be charged through a series resistance of the second charging resistor and the third charging resistor.
7. The electronic circuit unit according to claim 1 , wherein
the circuit module is configured to be switched from the power-saving mode to the operating mode in response to the switching pulse signal with a high level,
the semiconductor switching element is configured to cause the switching pulse signal with a high level to the start-up terminal upon being turned on, and
the one-shot pulse circuit is configured to charge the first coupling capacitor through the first charging resistor to switch the start-up terminal from the high level to a low level.
8. A battery pack comprising:
the electronic circuit unit according to claim 1 ; and
a chargeable battery, wherein
a voltage of the voltage is configured to be supplied to the electronic circuit unit and the semiconductor switching element.