Charge and discharge control circuit

• US 5,959,437 A
• Filed: 02/09/1998
• Issued: 09/28/1999
• Est. Priority Date: 02/10/1997
• Status: Expired due to Term

• Current Assignee: SII Semiconductor Corporation
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Hamaguchi, Masanao
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): SHIN, KYUNG E
• Application Number:
  US09/020,710
• Time in Patent Office: 596 Days
• Field of Search: 320/164, 320/162, 320/163, 320/146, 320/155, 320/157, 320/158, 320/159, 320/128, 320/132, 320/133, 320/134, 320/DIG. 13
• US Class Current: 320/134
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence

Abstract

To obtain a required delay time at each control using one capacitor in common, a charge and discharge control circuit includes an overcharge detecting circuit, an overdischarging circuit, and an overcurrent detecting circuit and carries out charge and discharge control of a secondary cell by ON/OFF control. A delay circuit includes plural current sources or a resistor and a single capacitor to obtain a varying delay time in response to a signal from outside. The charge and discharge control circuit operates the delay circuit so that a required delay output is obtained from the delay circuit by a first control circuit and ON/OFF controls a switch circuit by a second control circuit so that a required charge and discharge control is carried out with delay by the delay output.

Claims

1. A charge and discharge control circuit for controlling a charge and discharge of a secondary cell connected to an external power source terminal through a switch circuit by ON/OFF controlling the switch circuit, comprising:

an overcharge detcting circuit for detecting whether the secondary cell is in an overcharge state;

an overdischarge detecting circuit for detecting whether the secondary cell is in an overdischarge state;

an overcurrent detecting circuit for detecting whether overcurrent flows from the secondary cell to a load;

a delay circuit including plural current sources or a resistor and a single capacitor to obtain a selectively varying delay time in response to an external signal;

first control means for responding to each output of the overcharge detecting circuit, the overdischarge detecting circuit, and the overcurrent detecting circuit, and for operating the delay circuit so as to obtain a required delay output; and

second control means for responding to the output of the first control means and the delay output from the delay circuit, and for outputting a control signal for ON/OFF controlling the switch circuit.

2. A charge and discharge control circuit for controlling a charge and discharge of a secondary cell connected to an external power source terminal through a switch circuit by ON/OFF controlling the switch circuit, comprising:

an overcharge detecting circuit for detecting whether the secondary cell is in an overcharge state;

an over-discharge detecting circuit for detecting whether the secondary cell is in an over-discharge state;

a delay circuit including plural current sources or a resistor and a single capacitor to obtain a selectively varying delay time in response to an external signal;

first control means for responding to each output of the overcharge detecting circuit and the over-discharge detecting circuit, and for operating the delay circuit so as to obtain a required delay output; and

second control means for responding to the output of the first control means and the delay output from the delay circuit, and for outputting a control signal for ON/OFF controlling the switch circuit.

3. A charge and discharge control circuit for controlling a charge and discharge of a secondary cell connected to an external power source terminal through a switch circuit by ON/OFF controlling the switch circuit, comprising:

an overcharge detecting circuit for detecting whether the secondary cell is in an overcharge state;

an over-current detecting circuit for detecting whether over-current flows from the secondary cell to a load;

a delay circuit including plural current sources or a resistor and a single capacitor to obtain a selectively varying delay time in response to an external signal;

first control means for responding to each output of the overcharge detecting circuit and the over-current detecting circuit, and for operating the delay circuit so as to obtain a required delay output; and

second control means for responding to the output of the first control means and the delay output from the delay circuit, and for outputting a control signal for ON/OFF controlling the switch circuit.

4. A charge and discharge control circuit for controlling a charge and discharge of a secondary cell connected to an external power source terminal through a switch circuit by ON/OFF controlling the switch circuit, comprising:

an over-discharge detecting circuit for detecting whether the secondary cell is in an over-discharge state;

an over-current detecting circuit for detecting whether over-current flows from the secondary cell to a load;

a delay circuit including plural current sources or a resistor and a single capacitor to obtain a selectively varying delay time in response to an external signal;

first control means for responding to each output of the over-discharge detecting circuit and the over-current detecting circuit, and for operating the delay circuit so as to obtain a required delay output; and

second control means for responding to the output of the first control means and the delay output from the delay circuit, and for outputting a control signal for ON/OFF controlling the switch circuit.