Charging and discharging control circuit and charging type power supply device

• US 20050068008A1
• Filed: 09/16/2004
• Published: 03/31/2005
• Est. Priority Date: 09/17/2003
• Status: Active Grant

• Current Assignee: Ablic Inc. (MinebeaMitsumi Inc.)
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Zhang, Wei
• Granted Patent: US 7,301,306 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

There are provided a charging and discharging control circuit and a charging type power supply device, which are capable of switching between a normal state and a test state without adding an external terminal for testing. A detection circuit for detecting a voltage higher than an over-charge detection voltage of a secondary battery is provided in the charging and discharging control circuit. A voltage higher than the over-charge detection voltage is applied to a battery connection terminal of the charging and discharging control circuit to switch between a normal application state and the test state. A fuse is further provided in the charging and discharging control circuit to switch between two delay time shortening modes for testing according to the presence or absence of the fuse.

Claims

1. A charging and discharging control circuit equipped with a plurality of over-charge detection circuits for monitoring a plurality of secondary batteries, a delay circuit for generating a delay time in response to outputs from the over-charge detection circuits, and a charging and discharging switch control circuit for controlling a switch circuit in response to the outputs from the over-charge detection circuits and an output from the delay circuit, the charging and discharging control circuit comprising:

a plurality of detection circuits for detecting a voltage higher than an over-charge detection voltage of each of the secondary batteries; and

a circuit for switching between a normal state for controlling charging and discharging of the secondary batteries and a test state for evaluating a characteristic of the charging and discharging control circuit in response to signals from the plurality of detection circuits.

2. A charging and discharging control circuit according to claim 1, wherein the charging and discharging control circuit is set to the test state when a first detection circuit of the plurality of detection circuits detects the voltage higher than the over-charge detection voltage.

3. A charging and discharging control circuit according to claim 2, wherein the charging and discharging control circuit is set to the normal state when a second detection circuit of the plurality of detection circuits detects the voltage higher than the over-charge detection voltage.

4. A charging and discharging control circuit according to claim 1, further comprising a holding circuit for holding a state of the charging and discharging control circuit.

5. A charging and discharging control circuit according to claim 1, wherein the delay circuit comprises an oscillator circuit and the charging and discharging control circuit further comprises acceleration means for increasing an oscillating frequency of the oscillator circuit when the charging and discharging control circuit is in the test state.

6. A charging and discharging control circuit according to claim 1, wherein the delay circuit comprises a counter circuit and the charging and discharging control circuit further comprises a fuse and delay time mode switching means for switching between stages of the counter circuit based on presence or absence of the fuse when the charging and discharging control circuit is in the test state.

7. A charging type power supply device, comprising:

a switch circuit and a secondary battery which are connected in series with an external power supply terminal; and

the charging and discharging control circuit according to claim 1, which is connected in parallel with the secondary battery to control the switch circuit.