JPS59106829A - Charger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention relates to a charging device for a rechargeable electric razor, hair clipper, etc., and the present invention relates to a charging device for a rechargeable electric shaver, hair clipper, etc. To provide a charging device capable of charging up to 100 yen, and rapidly charging while preventing overcharging.

In recent years, there has been a remarkable trend toward portability of electrical devices, and many of these devices are equipped with rechargeable batteries, and the charging equipment that charges these rechargeable batteries requires a charging voltage that reaches a predetermined value in order to shorten charging time. The device is equipped with a so-called quick charging circuit that detects the current and stops charging.

In this case, the problem is that the apparent charging voltage at the time of charging completion fluctuates depending on the ambient temperature and self-heating temperature, and the detection unit that detects this charging voltage also has its own temperature fluctuations, so the OC Accurate detection cannot be performed in such a low temperature range or in a high temperature range such as 40°C.

As a countermeasure for this, a configuration has been proposed in which a diode is used as a reference voltage for comparison and detection with the charging voltage, and the voltage across the diode decreases as the ambient temperature rises, similar to that of a rechargeable battery.

However, the temperature coefficient between a rechargeable battery and a diode is not constant over the entire range from low to high temperatures.
Particularly in a low temperature range such as 0° C. to 10° C., the charging voltage appears high and there is a tendency for insufficient charging to occur.

This invention was made in view of these points,
It includes a detection section that generates an output signal in response to the charging voltage, and a control section that controls the charging current to the rechargeable battery based on the output signal of the detection section, and the detection section is connected to the signal input terminal side of the detection semiconductor element. At the same time, a first reference voltage section having a positive temperature characteristic and a second reference voltage section having a negative temperature characteristic are connected to the signal output end side, and the signal output terminal is connected to the rechargeable battery. 61j, Question 1 and the temperature characteristics of the sum of the 1st and 2nd reference voltage sections above are made to almost match the temperature characteristics of the charging voltage at the time of charging completion, and the reference voltage is made to follow the fluctuations of the charging voltage over almost the entire temperature range. It can be recharged.

Embodiments of the present invention will be described below with reference to the drawings.

In Figure 1, P is a commercial power supply, TR is a step-down transformer, and from one of its secondary sides, a rectifier diode DO, a charging current limiting resistor RO, a control transistor QO, and a rechargeable battery such as a nickel-cadmium battery are connected. It is connected to the other side via B.

Dz connected to the limiting resistor RIO is a Zener diode and constitutes a first reference voltage section K having a positive temperature coefficient, and is connected to the resistor Rq via a resistor R8.

A second group 4 having a negative temperature coefficient consisting of a varistor Dν
! ! Connected to voltage section ■7.

R7 is the bias resistor of the control transistor QO,
This resistor R7 and the transistor QO constitute an il control section that limits the charging current to the rechargeable battery B.

A detection section N is connected between the control section M and the second reference voltage section I.

The rechargeable battery B is connected to the signal input terminal U of the detection semiconductor element Q2 of this detection section N, and the first
The second reference voltage section is connected to the second reference voltage section.

And the temperature coefficient of rechargeable battery B is - from 0°C to 40°C.
3.5mV/'C, whereas the temperature coefficient of the first reference voltage section K (Hitachi HZ-11) is +5mV.
/'C, second reference voltage section L (Hitachi MHV-23
> is -2mV/'C, and furthermore, the signal terminal and output terminal U of the above-mentioned detection semiconductor element Q2 (2SC2309)
, V is selected to be -2,0 mV/°C.

Here, since the voltage at the first reference voltage section is divided by the resistor R8°R9 and the varistor Dν, the temperature coefficient at the first reference voltage section also appears as a divided one, so that the output fli! The temperature coefficient generated at lIV is the sum of the temperature coefficient of the second reference voltage section -2.0 mV/°C, and when the temperature coefficient of the semiconductor element Q2 is further added, it becomes almost equal to the temperature coefficient of the rechargeable battery B.

Therefore, the charging current charges the rechargeable battery B via the resistor RO and the control transistor QO, and the charging state progresses. When the voltage increases during charging of the rechargeable battery B, the voltage due to L is compared with the charging voltage in the 1.2 reference voltage section, and if the charging voltage exceeds this, the detection semiconductor element Q2 of the detection section N is
becomes conductive, thereby bypassing the hess current of the transistor QO of the control unit M and turning it off, completing charging.

The feature of the present invention is to match the temperature coefficient between the charging voltage, which varies depending on the ambient temperature at the time of detection, and the reference voltage. By combining them, it is possible to follow rechargeable battery B more precisely and precisely.

FIG. 2 shows another embodiment, in which a transistor type inverter circuit M' is used as the control section, and the same parts as in the previous embodiment are given the same reference numerals.

In FIG. 2, R1 and CI constitute a filter section for preventing noise interference, and a commercial power supply P is supplied to an inverter circuit M' using a transistor Q1 via a rectifying bridge DI. In the inverter circuit M, C2 is a smoothing capacitor, R2, C3 is a surge absorbing resistor and capacitor connected to both ends of the primary winding L1, R3 is a protective resistor, and a Zener diode is connected to the heath of the transistor Q1. It limits the supply current of Dz, and connects resistors R7, R5, R
4. Capacitor C4 and feedback winding LO are connected.

The secondary winding L2 is connected to the rechargeable battery B via a rectifying diode D2, and the primary winding L1. Feedback winding LO
, are wound around the same magnetic core.

Therefore, this inverter circuit M' first consists of a resistor RIO
, R7, R5, the transistor Q1 is biased and starts oscillating, and a stepped-down charging output voltage is generated in the secondary winding L2 to charge the rechargeable battery B. As the charging state progresses, the voltage applied to the input terminal U of the detection section N increases, and the first
, 2 reference voltage section, I, and detection semiconductor element Q2
becomes conductive, thereby bypassing the bias current, stopping oscillation, and completing charging, and this detection process is the same as in the previous embodiment.

As described above, the present invention includes a detection section N that generates an output signal in response to a charging voltage, and a control section M that controls the charging current to the rechargeable battery B based on the output signal of the detection section N. In the above-mentioned detection section N, the signal power 1 of the detection semiconductor element Q2
'f! The rechargeable battery B is connected to the JU side, and the first reference voltage section 91S has a positive temperature characteristic on the signal output terminal V side, and the second reference voltage 91S has a negative temperature characteristic.
, and make the temperature characteristics of the sum of the signal line, the output terminals U and V, and the reference voltage section 1 (1. Accordingly, in response to changes in ambient temperature, the reference voltage necessary for detection can be made to follow the rechargeable battery well, and over- and under-charging can be prevented.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a charging device according to an embodiment of the invention, and FIG. 2 is a circuit diagram of a charging device according to another embodiment of the invention. B...Rechargeable battery L (...First reference voltage section L...Second reference voltage section M...Control section N...Detection section Q2...Semiconductor element for detection U...・Input end■...Output end. Representative applicant Kyushu Hitachi Maxell Co., Ltd. Representative Fukuhara
Takashi Knee 1/

Claims (1)

[Claims] The detection unit N includes a detection unit N that generates an output signal in response to a charging voltage, and a control unit M that controls charging current to the rechargeable battery B based on the output signal of the detection unit N, and the detection unit N includes a detection semiconductor element. The rechargeable battery B is connected to the signal input terminal U side of Q2, and the signal output terminal V side is connected to a first reference voltage section having positive temperature characteristics and a second reference voltage section having negative temperature characteristics. The temperature characteristics of the sum of L are approximately the same as the temperature characteristics of the charging voltage at the time of completion of charging. Charging device.