JPH06217465A - Power supply circuit - Google Patents

Abstract

PURPOSE:To provide a power supply circuit in which noise or ripple on an AC line has no effect on the operation of a load circuit. CONSTITUTION:The power supply circuit comprises a charging circuit 4 for a battery 5, a power switch 6 provided on a line for leading the output from the battery 5 to a load, a circuit 7 for detecting the voltage across the power switch 6, and means for stopping the operation of the charging circuit 4. When the power switch 6 is turned ON, the voltage detecting circuit 7 controls the charge stopping means to stop charging operation of the battery 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit device,
More specifically, it relates to a power supply circuit device capable of reducing noise when charging a battery and AC line noise.

[0002]

2. Description of the Related Art FIG. 2 is a circuit diagram showing a configuration of a conventional power supply circuit device for supplying energy stored in a battery to a load. In FIG. 2, 51 is a power plug, 52 is a power cord, 53 is a transformer, and 54 is a charging circuit. The charging circuit 54 is provided with a rectifier circuit (not shown) for converting an AC power supply into a DC power supply, and a charging control unit (not shown) for controlling charging of the battery 55.

Reference numeral 56 is a power switch, 57 is a voltage detection circuit for detecting the voltage of the power supply line 58, and 59 is an overcharge prevention circuit for preventing overcharge of the battery 55.

Next, the operation will be described. Power plug 5
When 1 is connected to an AC 100V AC power supply, this AC power supply is converted into a low-voltage AC voltage by a transformer 53,
It is supplied to the charging circuit 54.

In the charging circuit 54, the supplied AC voltage is converted into a DC voltage by a rectifying circuit and the battery 55 is supplied.
A predetermined voltage is applied to. When detecting that the voltage level of the power supply line 58 has become lower than a predetermined level, the voltage detection circuit 57 outputs a charging start command signal to the charging control unit of the charging circuit 54.

To stop charging, the voltage detection circuit 57 detects a predetermined voltage, and the overcharge prevention circuit 59 detects that the voltage level of the power supply line 58 has become higher than a predetermined level. The overcharge prevention circuit 59 is configured to control the charging control unit of the charging circuit 54 to reduce the charging current of the battery 55.

[0007]

The conventional power supply circuit device described above has the following problems. That is, when the power switch 56 is turned on and energy is being supplied from the battery 55 to the load, when the voltage detection circuit 57 detects that the voltage of the power supply line 58, that is, the battery voltage has dropped below a predetermined level, voltage detection is performed. Circuit 57
Outputs a charge start command signal to the charge control unit of the charging circuit 54, so that energy is supplied to the load from the battery 55 and the charging circuit 54 while charging is being performed.

In particular, since noise at the time of charging and AC line noise and ripples flowing from the side of the AC power source are superimposed on the output of the charging circuit 54, the AC line noise and ripples affect the operation of the load circuit. When the load is a preamplifier, the S / N ratio is deteriorated and the purpose of using the battery 55 as a power source is diminished.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a power supply circuit device in which AC line noise, ripple, etc. do not adversely affect the operation of the load circuit. Especially.

[0010]

SUMMARY OF THE INVENTION A power supply circuit device according to the present invention detects a battery charging circuit, a power switch provided on a line for guiding the output of the battery to a load, and a voltage across the power switch. It comprises a voltage detection circuit and a charging stop means for stopping the charging operation of the charging circuit. When the power switch is in the ON state, the voltage detection circuit controls the charging stop means to stop the charging of the battery. It is characterized by being configured as described above.

[0011]

According to the present invention, the battery is charged only when the energy supply to the load circuit is stopped, and the battery charge is stopped when the energy supply to the load circuit is performed. Therefore, noise such as hum does not enter the load circuit from the power line.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing the configuration of the power supply circuit device in this embodiment. In FIG. 1, 1 is a power plug,
Reference numeral 2 is a power cord, 3 is a transformer, and 4 is a charging circuit for converting the output of the transformer 3 into direct current and for charging the battery. And 5 is a rechargeable battery.

Further, 6 is a power switch provided on the power supply line between the charging circuit 4 and the load circuit, and 7 is a switch which detects whether the power switch 6 is in an on state or an off state through a transistor Tr and charges the battery. A voltage detection circuit that detects the voltage of the voltage line 8 to which the (+) terminal of the battery 5 is also connected, which is the output line of the circuit 4, and 9 is the voltage of the voltage line 8 that charges the battery 5 within a predetermined range. The over-charge prevention circuit 10 monitors as described above, 10 is a switch provided between the transformer 3 and the charging circuit 4, 11 is a voltage detection circuit 7 that detects a predetermined voltage of the load-side voltage line 12 of the switch 6. This is a switch control circuit for controlling the switch 10 to the off state when the switch 10 is turned on. Further, in this embodiment, when the voltage on the voltage line 8 exceeds a predetermined voltage level, the overcharge prevention circuit 9 turns off the switch 10 via the switch control circuit 11.

In the power supply circuit device configured as described above,
When the power switch 6 is in the off state, the voltage of the power line 12 on the load side is equal to or lower than the predetermined voltage, so the voltage detection circuit 7 controls the switch 10 to be in the on state and the battery 5 is in the charging state. When the power switch 6 is on, the switch 10 is off, and the battery 5 supplies power to the load.

As described above, when energy is supplied from the battery 5 to the load circuit, charging to the battery 5 is stopped, while battery 5 is not supplied to the load circuit. Since the charging is performed to the load circuit, noise and ripples in the power supply line do not adversely affect the load circuit.

In order to supply energy to the load circuit for a long time, the battery 5 should preferably have a sufficiently large capacity in this case.

[0017]

As described above, according to the present invention,
Since it is configured to stop charging the battery when it is determined that energy is being supplied to the load, and to start charging the battery when it is determined that energy is not being supplied to the load. This has the effect of preventing adverse effects on the load due to power line noise and ripple that sneak in from the side.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a power supply circuit device according to the present invention.

FIG. 2 is a circuit diagram showing a conventional power supply circuit device.

[Explanation of symbols]

 4 Charging Circuit 5 Battery 6 Power Switch 7 Voltage Detection Circuit 10 Switch 11 Switch Control Circuit

Claims (1)

[Claims] 1. A charging circuit for a battery, a power switch provided on a line for guiding the output of the battery to a load, a voltage detection circuit for detecting a voltage across the power switch, and a charging operation of the charging circuit is stopped. A power supply circuit device comprising a charging stopping means for controlling the charging, and the voltage detecting circuit controls the charging stopping means to stop charging of the battery when the power switch is in an ON state.