JPS60106339A - Solar battery charging control circuit - 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 provides a circuit for excitation verification at low voltage of a short-circuiting element for overcharging prevention for a secondary battery or a capacitor charged by a solar cell. This is what we provide.

Conventionally, in order to prevent catastrophic charging at any point in the process of charging a secondary battery or capacitor with a solar battery, the voltage f of the secondary battery or capacitor is detected, and when the voltage exceeds a certain level, the anode of the solar battery is Short the cathode and
There is a circuit that prevents it from charging any further. Figure 1 shows its configuration.

In FIG. 1, a shorting element 5 is connected in parallel with the solar cell 1, and the first three of the shorting elements 5 are connected to the output of the overcharge prevention circuit B. 7 is a secondary battery or a capacitor, and 8 is a load. -1: 9 is a diode that prevents current from flowing backward from the secondary battery or capacitor 7 to the solar cell 1. In FIG. 1 (cL), the overcharge prevention circuit 6 is driven by the voltage immediately after the diode 9.
In (b), it is driven by lightning pressure just before the diode 9, that is, by the voltage of the solar cell 1.

In the circuit shown in FIG. 1 (α), when the electromotive voltage of the solar cell 1 and the voltage of the secondary battery or capacitor 7 are at voltages that cannot sufficiently drive the overcharge prevention circuit 6, the output of the overcharge prevention circuit is unstable. Therefore, it is unclear whether the shorting element 5 is on or off. Now, when the hooking element 5 is in the on state, the solar cell 1
Even if the solar cell is exposed to light, since the solar cell is short-circuited by the short-circuiting element 5, charging cannot be performed at all.

In FIG. 1(b), the J view similar to U) is also considered. Therefore, in the circuit shown in FIG. 1, when the voltage of the solar cell 1, the secondary battery, or the capacitor 7 is sufficiently low, there is a risk that the charging function will not be achieved at all.

The present invention eliminates such drawbacks, and at low voltage K i
The present invention provides a circuit that controls a shorting element so that it is always charged even when the shorting element is charged.

The present invention will be described in detail below with reference to the drawings.

FIG. 2 shows a circuit around short-circuit control when configured with complementary MO8. P-channel MO8FE as shorting element 5
T'ft is used. The gate terminal of the first electrode 6I''t turns on when the gate voltage drops below the voltage of the source terminal of the second electrode 2 to a value below the voltage of the source terminal of the second electrode 2, shorting the two terminals of the solar cell.

Now, when the normal pressure of the solar cell 1 and the secondary battery or capacitor is smaller than the sum of the six voltage values for both PN and PN, the potential of the output terminal 23 of the overcharge/redundancy prevention control circuit B is the potential of the source terminal 2 of the shorting element. Therefore, the potential of the drain terminal 4 does not tend to change. Now, the electromotive voltage of the solar cell 1 is higher than the threshold voltage of the shorting element 5.
However, when the voltage of the output terminal 23 of the overcharge prevention circuit B is lower than the sum of the threshold voltages of the PN transistors constituting the overcharge prevention control circuit 6, the resistor Without the means 26, the shorting element 5 would turn on;
The electromotive force of the solar cell is consumed by the shorting element 5, resulting in the secondary battery or capacitor not being fully charged.

Here, the resistor means 26 is connected between the source and the gate of the shorting element 5, and when the current driving capability of the N-channel transistor 24 of the overcharge prevention control circuit 6 is actually close to the overcharge prevention +L I, voltage. Gate 1! By setting the potential of the pole 3 to be the potential of the drain electrode 4, it is possible to prevent the shorting element 50 from turning on at low voltages.

For example, the lightning current driving capability of the N-channel transistor 24 is
kexd =-! ! ! -(va8-Vth)2. Here, V(18 is the voltage between the N-channel transistor and the source, Vth of the gate 2 of the gate 24 is the threshold voltage, and βN is the current drive coefficient.

Now, if you want to turn on the shorting element 5 when the voltage is 1.8 V, Vth, = 0.5 V, βN = 10-'A
/V', VGllI=1.8 V, the current is d-0845 μA. At this time, in order to keep the potential of the gate voltage wL3 below 0.1 V, the resistance value R of the resistor means 26 becomes R22 MΩ. Therefore, by setting the resistance value of the resistance means 26 to 2M, Q, the short-circuiting element 5 does not malfunction and fully exhibits its function even at a voltage of 1°C where the overcharge prevention control circuit 6 does not operate satisfactorily. be able to.

Moreover, since it is the time of overcharging prevention, the reactive current flowing through the resistance means 26 has no influence on the charging 1 function.

This resistance means 26 can be formed by impurity diffusion into the wafer substrate or by high resistance polysilicon. Furthermore, accurate parentage can be achieved using depression type MOS transistors.

In FIG. 3, an N-channel MO8FFi is used as the shorting element 5.
In this example, the resistance means 26 is connected between the gate electric body 3 and the drain electrode 4 to prevent malfunction of the shorting element.

In this case as well, the method for setting and realizing the value of the resistance means 26 is as follows.
This is the same as the case shown in the figure.

Although an example of the configuration using complementary MO8 has been shown above, other configurations, such as bipolar elements, can also be used. Furthermore, M
It is also possible to configure a mixture of O8 and bipolar. In the case of a mixture of MOS and bipolar, depending on the charge supply capacity of the solar cell or the current consumption of the load, for example, the short circuit element may be a bipolar transistor, and the overcharge prevention control circuit may be configured with MOS to prevent overload. The power consumption of the charging prevention control circuit can be reduced, resulting in an advantageous configuration in terms of current consumption.

As described above, according to the present invention, a circuit that performs reliable charging at low voltage and voltage can be implemented by adding one resistor means, and can be implemented in a practical manner. Use the pond f for fC various devices 1
It can be used with great effect.

[Brief explanation of the drawing]

Figure 1 of Asahi (a) (b)...Gronk configuration diagram of a charging circuit using solar cells 1...Solar cell 5...Short circuit element 6...Control to prevent poor charging Circuit 7... Load 8... Power storage means 9... Backflow prevention diode Figure 2: Configuration diagram around the short-circuit element control circuit of the charging circuit of the present invention 1... ...Solar cell 5...Short-circuit element 26 composed of P-channel MO8I1mT...Resistance means for preventing malfunction Fig. 3...Configuration diagram around the short-circuit element control circuit of the charging circuit of the present invention 5... Short-circuiting element or more consisting of N-channel MOS FET Applicant: Suwa Seikosha Co., Ltd. (α) Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A solar cell, a power storage means that is charged by lightning generated by the solar cell, an overcharge prevention 11 control circuit, and an output of a 6tTN self-overcharge prevention control circuit are connected to a first electric connection, and a second electric connection.
and a sixth electrode are respectively connected to the anode and cathode of the solar cell, and the charging circuit has a shorting element that shorts the anode and cathode of the solar cell depending on the output state of the circuit. , the first of the shorting elements
1. A solar cell charging flai control circuit, characterized in that the electrode of the battery is connected to the anode or cathode of a large 1-tube pond by a resistive means.