JPS6289433A - 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 [Technical Field 1] The present invention relates to a charger using a SW/Nanda regulator circuit equipped with a step-up transformer [Background Art 1 Conventional Art 1. This type of charger is shown in Figure 2 1, '1-, which has a direct voltage lance T (1 large turn #i++-+ and a switch 7 nang tran) at both ends of the voltage lance T. Connect the series circuit with Nostar Q1 and connect step-up transformer T 3 between the base and emitter of switching transformer Nostar 01.
The next winding is the feedback winding I15, the capacitor C3, and the base resistor l. Connect the series circuit of , DC power supply 1:, is supplied, and the switching trannostar 01 is started by the starting resistor R. This induces in the winding 1.3.: This causes the feedback of the switching transistor 011 and 211 to oscillate, and the oscillation of the switching transistor 0. The current flowing in the large winding Ml, 1 causes the 2 large windings of the step-up transformer T #I1.2
1, this induced voltage is half-wave rectified by a diode 1), and is converted by a capacitor C to obtain a voltage r, = It. ]Here, 1. In the switching regulator circuit 1 described above, the secondary winding ■4. The energy stored in the battery is released to the storage battery II when the switching transistor Q1 is turned off. In addition, in this conventional example, the power storage is 1'll
An output open protection circuit 3 for preventing the switching regulator circuit 1 output from rising abnormally when B+ is disconnected and L-; and a charging control circuit 2 for preventing the M battery 131 from being overcharged. It is equipped with Output open protection circuit; 3 is a switching regulator circuit 1 output with Zener diode Z I) and capacitor C
A transistor Q is connected between the base and emitter of the switching transistor Q1 by connecting a series circuit with Q1.
The base of the capacitor C2 is connected to the connection point of the Zener diode Zl') and the capacitor C2. In operation, when the storage battery [31 is disconnected and the output of the switching regulator circuit 1 is placed in a no-load state, the voltage between the open terminals abnormally increases by l-. This release #A7! - The voltage between the Zener diode Z I')
1, Then, capacitor C2 is charged, and when the voltage across this capacitor C2 becomes lower than the threshold value of transistor Q3, the transistor (19) becomes conductive, and the switching transistor (19) becomes conductive. Bypasses the base voltage IIt, which is supplied by the feedback winding I4.
7, the switching of the switching transistor Q is stopped 1'. Therefore, due to the stopping of switching of the switching transistor Q1, the output of the switching regulator circuit 1 is also stopped. Furthermore, the charging control circuit 2' is specifically a comparator CI that compares the output voltage of the switching regulator circuit 1 with a reference voltage.
] and this comparator Cl], which has a small output and a transistor Q2 which shorts the base and emitter of the switching transistor (Q2). Therefore, the power supply voltage of the comparator Cl) needs to be higher than the output of the switching regulator circuit 1. Therefore, a fourth winding I, 4 is provided in the external pressure transformer 1.
Next volume M 1. , the boost voltage is obtained at diode I)2
And the voltage rectified and smoothed by capacitor C5 was connected to the power supply =3=. The operation of this charging control circuit 2' is such that when the output of the switching regulator circuit 1 is lower than a predetermined voltage determined by the reference voltage (L:1m-1:H), the output of the comparator cP becomes high level, and the transistor Q2 becomes conductive (this causes the switching By speeding up the cut-off of the transistor Q1, the on-period of the switching transistor 01 is shortened, the charging current flowing to the storage battery [31] is reduced, and the storage battery B1 is prevented from deteriorating due to heat generation or the like.

[7]-In the charger described above, the fourth winding T5. This increases the size of the step-up transformer T, leading to an increase in the size of the HH, and also necessitating the provision of both the charging control circuit 2° and the output open protection circuit 3, which complicates the circuit configuration. There was an order.

[Objective of the Invention 1 The present invention has been made in view of the above-mentioned points, and its object is to simplify the circuit configuration by sharing the charging control circuit and the output open protection circuit. The purpose of the present invention is to provide a charger that can be made smaller.

[Disclosure of the Invention 1 (Embodiment) Fig. 1 is a diagram showing an embodiment of the present invention. In this embodiment, a resistor consisting of resistors R, , R5 is connected to the output of a switching regulator circuit 1 similar to the conventional example. In the conventional example, the transistor Q2 is controlled by the output of the comparator CP, which connects the voltage circuit 4 and compares the voltage at the voltage dividing point of the resistor I This circuit is equipped with a charging control circuit 2 that also functions as the charging control circuit 2 and the output open protection circuit 3 described above. connects diode r)4. This diode D has a charge RB 13 + of a predetermined value or more1. This is a diode for the backflow prevention 11 to prevent the electric charge charged in the storage battery B from being discharged through the resistor R+-Rs of the voltage dividing circuit 4 when the storage battery B is charged.

In addition, a capacitor C1 is connected across the resistor R5 of the voltage dividing circuit 4.
[7] is connected to prevent noise such as ripple components included in the output of the switching regulator circuit 1 (τJ: 11.) to prevent the recomparator CP from malfunctioning, not operating stably, or becoming stuck.In addition, the comparator O13 The charge control circuit 2 monitors the voltage divider circuit/1 output at 17 to detect overcharge status etc. using the voltage divider circuit 1, so there is no need to increase the power supply voltage, so the voltage of the DC power supply 1 is used. ing.

The following describes the code operation. The voltage raised by the switching regulator circuit 1 is applied to both ends of the W*flood B1, and at the same time, this voltage is also applied to the voltage dividing circuit 4. Therefore, when the voltage divided by the resistors R4 and R of this voltage dividing circuit 4 is checked by the comparator 1, and if this divided voltage becomes higher than the reference value, the external voltage is output by the external comparator (
-] The P output becomes high level and conducts the transistor 02, thereby bypassing the base current of the switching transistor Q.
Switching control of the switching transistor Q1 is performed by turning off the transistor Q1.

Now, suppose that the storage battery is being charged by connecting it to the output of the switching regulator circuit 1, and when the storage battery MB reaches a fully charged state, the voltage dividing circuit 4 and the switching control circuit 2 will operate as -1: Switching transistor (
Bypassing the base current of the switching transistor O1, the transition to the off state of the switching transistor O1 is made faster than the switching period of the switching regulator circuit 1.

For this reason, the energy accumulated in the secondary winding 1.2 of the step-up transformer 'r becomes smaller, and the photoelectric current of the storage battery l (I also becomes smaller. Therefore, the M battery +3. will not be overcharged. .

Next, when the switching regulator circuit 1 is operating in a state where the storage battery B1 is disconnected from the switching regulator circuit 1 output, the switching regulator circuit 1 output is detected by the voltage dividing circuit 4 in the same manner as described in -1-, This time, storage battery B1 is switching regulator circuit 1
Since it is not connected to the output, a divided voltage exceeding the reference voltage is always applied to the comparator CT,). Therefore, the output of the comparator C)) maintains a high level state, and the switching of the switching transistor Q1 is completely stopped in order to maintain the conductive state of the transistor Q2. Therefore, it is possible to prevent 11. the output voltage of the switching regulator circuit 1 from rising abnormally and damaging the circuit components. By monitoring the voltage obtained by dividing the output voltage of the switching regulator circuit 1 in the voltage dividing circuit 4 in this way, for example, when the battery voltage is 12V and the power supply of the comparator is 10V, the voltage division circuit 41 If the voltage is divided by /2, the reference voltage can be set to 6V, and there is no need to particularly reduce the voltage of the comparator CP, and therefore there is no need to provide a quaternary winding in the external voltage transformer I. In addition, by using the charging control circuit 2 that also functions as charging control and output open protection operation, the circuit configuration can be simplified.
This is effective in reducing the size of the device and reducing costs.

[Effects of the Invention 1] As stated in -L, the present invention includes a switching regulator circuit using an external voltage transformer, a voltage dividing circuit comprising a resistor that divides the output voltage of the switching regulator circuit,
Since it is equipped with a charge control circuit that compares the output of the voltage divider circuit with a reference voltage of -8 to control the switching of the switching regulator circuit, the voltage divider circuit divides the output voltage of the switching 1/Y regulator circuit. (by monitoring the voltage generated by switching control), if the voltage dividing ratio of the voltage dividing circuit is selected appropriately, there is no need to make the voltage type rE of the charging control circuit particularly high. There is no need to provide a winding to obtain the power supply voltage for the charge control circuit, and by making the charge control circuit function both for charge control and output open protection,
The circuit configuration can be simplified, which is effective in reducing the size and cost of the device.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention, and FIG. 2 is a circuit configuration diagram showing a conventional example. 1 is a switching regulator circuit, 2 is a charging control circuit, 41 is a voltage divider circuit, 1 is a DC power supply, `` is an external pressure transformer, Ql is a switching transistor, Q2 is a transistor, CI) is a comparator, D is a diode, C1
is a capacitor, and R4-R5 are resistors. Agent Patent Attorney Ishi 1) Ai 7-1+-. Figure 1-)' -w iD2 Engineering 1 Do-, %,) 7--------- A East-m-74/ ] l RI L+□JD1:::〕 □ cl:,・ZD '- 1〒BI E/ 1 C3R31: 1'': Q+ J l
1: : Q2 l-
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Claims (3)

[Claims] (1) A switching regulator circuit using a step-up transformer, a voltage dividing circuit consisting of a resistor that divides the output voltage of the switching regulator circuit, and controlling the switching of the switching regulator circuit by comparing the output of the voltage dividing circuit with a reference voltage. A charger comprising a charging control circuit. (2) The charger according to claim 1, wherein a diode for preventing backflow is inserted between the voltage dividing circuit and the storage battery. (3) The charger according to claim 1, wherein a capacitor is inserted between the voltage dividing point of the voltage dividing circuit and the negative electrode of the storage battery.