JPS6093668A - Driving circuit - Google Patents

Abstract

PURPOSE:To drive a motor by discharge of a capacitor even at the OFF of an electric power supply on the basis of a simple circuit constitution by operating the motor and a means to be driven automatically by an output from a holding means at the OFF of the power supply. CONSTITUTION:When the power supply 20 is turned off, a diode D11 is also turned off to prevent the charge of a capacitor C11 from discharging to the power supply side and the discharged current is made to flow from the capacitor C11 to the motor 21 through a resistor R14, a transistor (TR) Q3, the motor 21, a diode D12, and a TRQ6 to rotate the motor 21. Consequently, the motor 21 can be rotated by the discharge of the capacitor at the OFF of the power supply without a specific switching circuit like an ordinary case.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a drive circuit, which is used, for example, to drive a disc lifting mechanism of a video disc player. For equipment and machinery, in order to protect the equipment, machinery, and tools used, motors or solenoid devices may be used to change the setting status of equipment and machinery after turning off the power. - In a player, if the power is turned off while a video disc is placed inside, the video disc is supported and lifted by a turntable smaller in diameter than the video disc, which may cause deformation of the video disc. be. In order to prevent such deformation, the turntable is automatically lowered when the power is turned off so that the outer circumference of the video disc rests on the 70-inch board.

Conventionally, when the power is turned on, the solenoid is sucked to keep the disk in the raised state, and when the power is turned off, the solenoid is released to lower the disk, and when the power is turned on, the capacitor is charged. There is a method in which when the power is turned off, a motor is rotated by the discharge current of a capacitor to lower the disk.

Comparing these two methods, the solenoid method has a simple drive circuit, but requires a mechanism that uses the solenoid to maintain the raised state of the disk or the raised state of the seater table. This is disadvantageous in terms of reliability.

In the capacitor-based method, the motor used to raise and lower the disc and the turntable can be used, so there is no need for a special longevity mechanism, which is advantageous in terms of device size, cost, and reliability. There is a problem in that the circuit to do this becomes complicated.

FIG. 1 shows a conventional example of a method using a capacitor. No. 1 is driven by a motor, and when the power source 12 is on, it is driven by a motor drive circuit 13, and the disk can be raised or lowered. 14 is a switching circuit, transistors Q7, Q2, diodes DI, D2
゜DJ, D4, resistance R1, R,? , RJ, and a capacitor system.

Now, assuming that the forward voltage drop of the PN junction between the diode and the transistor is V, the case where the power is on and the case where the power is off will be explained.

(,) When the power is on, VJ>VJ-2V, so the transistor Q2 is turned off. If the motor drive circuit output voltage v is v1 - vF, the diode D3 is turned on, current flows from the drive circuit 13 to the motor 11, and the motor 1 is operated. Since the transistor Ql is turned on and the current flows from the motor 1 through the transistor Q and the diode D2 to the drive circuit, the motor 1 reverses. do. In this way, the motor 1 can be driven by the output voltage of the motor drive circuit 13. Furthermore, V
l, V2, V3, VJ.

V5, V6, V71d are the voltage values of each part shown in the figure. 1, -V, (V 1 (If V, then diode D2, trunks, Ql, and diode D3 are turned off at the same time, but normally v) Since vF is sufficiently small compared to v, it has a large effect on motor operation. Furthermore, capacitor C1 is charged from the power supply through diode D4.

(b) When the power is off.

Voltages Vl, V2, V3, and VJ are all approximately OV. At this time, since V7>VJ, diode D4
is off, V,? (V7-V, so the transistor Q2 turns on and the motor 11 is connected from the capacitor C to the resistor R.
3. A discharge current flows to the motor 11 through the transistor Q2. Also, since V 7 (v s + v,
Diode D3 is turned off, and furthermore, v2<v6+2vF
Therefore, transistor Q] is turned off to prevent discharge current from flowing into the motor drive circuit 13.

As described above, in the conventional capacitor system, in addition to the drive circuit that drives the motor when the power is turned on, a switching circuit using a transistor, a diode, and a resistor is separately provided. Therefore, the number of circuit components increases, and the advantages of the capacitor system, such as miniaturization, low cost, and high reliability, cannot be fully utilized.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a drive circuit that can drive a motor by discharging a capacitor even when the power is off, with a simple circuit configuration.

[Summary of the invention]

In this invention, when the power supply 20 is turned off, the motor 2 and the driven means 37 are automatically operated by the output of the capacitor C1l and the holding means 32, and can be easily incorporated into the drive circuit section. This is what was done.

[Embodiments of the invention]

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

In FIG. 2, 2o is a power supply υ, and 2no is a motor. The output terminal of the power supply 20 is connected to the anode of the diode D10.
It is also connected to one end of resistors R11 and R12.

Further, the cathode of the AiI diode 010 is grounded via the capacitor C1l, and the resistor R13,
FCl2. Connected to one end of each of R15 and R16.

The other end of the resistor R1l is connected to the control input terminal A and to the pace of the transistor Q4, and the other end of the resistor R12 is connected to the pace of the transistor Q5 and the collector of the transistor Q6.

Next, the other end of the resistor Ft13 is connected to the pace of the transistor Q3 and the collector of the transistor Q4, and the other end of the resistor Ft14 is connected to the collector of the transistor Q3. The other end of the resistor R5 is connected to the collector of the transistor Q5, and the other end of the resistor R76 is connected to the control input terminal B and the pace of the transistor Q6.

The emitter of the transistor Q3 is connected to one terminal of the motor 21 and the collector of the transistor Q4 via a diode I'Dll, and the emitter of the transistor Q5 is connected to the other terminal of the motor 2. and is connected to the collector of transistor Q6 via diode D12. Further, each terminal of the motor 21 is connected to a diode in the opposite direction.

014 to ground. Also, transistor Q4
, Q6 are each grounded.

An embodiment of the present invention is constructed as described above.

V8 to V14 shown in each part indicate the voltage of that part.

Next, the operation of the above circuit will be explained separately for when the power supply 20 is on and when it is off.

(a) When the power supply 20 is on.

Until the relationship V11=V12-V is established, the diode l)lO is turned on and the capacitor C1l is charged.
From this point on, Vll = V12-V.

It will be preserved. Here, transistors Q 4 and Q 6
, that is, when input terminals A and B are open, the pace of transistor Q4 is connected through resistor R11, 17=(V)2-V, )/R17 (R1) also means the value of resistor R11O. shall be.

) , the transistor Q4 is turned on.

At this time, since v9 becomes almost Ov, the transistor Q
No current flows at the pace of 3, and this transistor Q3 is turned off. Also, the pace current 12 of transistor Q6 is 1,? =(V77-v,)/ltz 6=(Vl2-
2V, )/R16 (R16 also means the value of resistor R16), transistor Q6 turns on, and transistor Q5
is turned off.

As a result of the above, when terminals A and B are open, motor 2
No power is supplied to motor 2, and motor 2 stops.

Next, a case where terminal A is grounded will be explained.

In this case, VB=0, i 1 =0, and transistor Q4 is turned off. At this time, transistor Q
3 operates as a common collector circuit, and the emitter is VlO=V11-i 3R14-V.

It will be preserved. If terminal B is left open here, transistor Q5 is off, and diode D12. Since the transistor Q6 is turned on, the motor 2 is connected to the power supply 20, the diode D10, the resistor FL14, the transistor Q3,
Current flows through the motor 2, diode D12, and transistor Q6. This causes the motor 21 to rotate.

Conversely, if terminal B is grounded and terminal A is open, transistors Q, 3. Q6 is turned off and transistor Q4,
Q5 is turned on. As a result, current flows through the motor 21 from the power source 20 through the diode D0, the resistor lζ15, the transistor Q5, the motor 21, the diode D1, and the transistor Q4. In this case, the current path is in the opposite direction compared to the previous case, so the motor 2 rotates in reverse.

Normally, control operations are performed in the three spindle modes described above, that is, stop, forward rotation, and reverse rotation.

If transistors Q4 and Q6 are grounded at the same time, transistors Q3 and Q6 are turned off. Q5 is turned on, and the voltages at both terminals of the motor are V10=V12-2V, V13=V
At 12-V, the potential difference is very small and the current path is not established, so the motor 2 does not rotate.

(b) Next, the case where the power supply 20 is turned off will be explained.

When the power supply 20 is turned off, V12 becomes almost Ov, but the capacitor C1l is already charged and V11=V
12-V, so the relationship vll>v12 holds true. Therefore, the diode Dll is turned off to prevent the charge in the capacitor C1l from being discharged to the power supply side. Here, current i1. Since i4 is 0 in V12, IJ=
i4=0, and transistors Q41Q5 are turned off. Also, the pace of transistor Q6 is l,? = (
A current of vIJ -V, )/R1ty flows, transistor Q6 is turned on, and the emitter of transistor Q3 has V10=V11-RJ, 9X13-V.

A voltage is generated. As a result, a discharge current flows through the motor 21 from the capacitor C1l through the resistor R14, the transistor Q3, the motor 2, the diode D12, and the transistor Q6, and the motor 2 rotates. Due to discharge,
When vll decreases, the motor current becomes 0, but the threshold value is determined by the PN junction characteristics of transistor Q3, diode D12, and transistor Q6, V11 = 3V.

As described above, in the present invention, there is no need to provide a special switching circuit as in the prior art, and the motor can be rotated by discharging the capacitor when the power is turned off. If you want the motor to rotate in the opposite direction to the previous operation when the power is turned off, replace resistor R1l and ELI2 with capacitor C1l.
Connect the resistors R13 and R76 to the output side of the diode D.
Just connect it to the anode side of the ID. Also, diode D
ll, D12 is the pace of transistors QJ, Q5.
It functions to suppress the emitter reverse bias voltage to within V, and protect the transistors Q3 and Q5. Furthermore, when the power is turned on, the capacitor C1l is connected to the A? It also serves as a power supply/mother capacitor that absorbs leakage current. The motor drive circuit of the present invention includes:
It is particularly suitable for pulse-width modulation drive methods that consume less power in the drive circuit elements, but in general, in this method, large current pulses equivalent to the motor starting current flow frequently through the circuit, passing through the power supply circuit, and these pulses are circuit operation. However, in this circuit, capacitor C1
The use of a relatively large 'II-fa capacitor as l is very advantageous in this respect.

In addition, the diode D13. D14 is used to quickly stop the motor by passing a current due to the electromotive force of the motor at the start of the motor stopping operation, and resistors R14 and F
Cl2 is a protective resistor for overcurrent prevention, and is not essential to the present invention together with the diodes D13 and D14.

Furthermore, in the above explanation, the capacitor C1l was used, but
It may be any other rechargeable battery such as a storage battery, and any holding means capable of holding voltage or current may be used.
Resistance Ft14. Tt15, diode I) 1,?
, D Z 4 can be omitted if there are no restrictions on overcurrent and stop time.

In the above description, a motor is used as an example of the driven object, but the motor 14 may be any other element or device that can be driven in an air-like manner.

The essence of the invention can be seen as shown in FIG. That is, 20 is a power source, directional intermittent and vli
It is connected to the note holding means 30.

Directional intermittent and power supply holding means 30 includes a holding means 32 that is excited by a power source and can hold charge, voltage, or current, and transmits the power supply voltage to the holding means 3 when the power supply is in operation, and when the voltage of the power supply decreases, it transfers the power supply voltage to the power supply 20. and directional disconnection means 3 for separating the holding means 32.

One terminal 37a of the driven means 37 is connected to one terminal of each controllable disconnecting means 33,34, and the driven means 3
The other terminal 37b of 7 has a controllable disconnection means, ? 5.
,? 6 are connected to each other. Controllable intermittent means 3,? , 35 is connected to the holding means 32.
1, which are commonly connected to one output terminal 32g of the controllable disconnecting means 34 and the other terminal of the controllable disconnecting means 34 and 36 are commonly connected to the other output terminal 3'2b side of the holding means 32. The disconnection means 33 to 36 each have a control terminal for turning on and off between one terminal and the other terminal. Control terminals of the controllable disconnection means 33 are terminals 321L, 3
7a, and the control terminal of the controllable disconnection means 34 is connected to one output terminal 20IL of the power supply 20,
Connected to external control terminal A. Further, the control terminal of the variable control intermittent means 35 is connected to the terminals 20g and 37b,
The control terminal of the variable control intermittent means 360 is connected to the terminal 32h and the external control terminal B.

〔Effect of the invention〕

As described above, the present invention eliminates the need for a special switching circuit, significantly reduces the number of parts, simplifies the configuration, and improves the stability of the power supply when the power is turned on and the reliability of the equipment accordingly. A useful driving circuit can be provided.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional drive circuit, FIG. 2 is a circuit diagram showing an embodiment of the present invention, and FIG. 3 is a diagram showing the basic configuration of the present invention. Q3~Q6...Trannosta, nil~n16...
Resistance, 010~1]14...Diode, C1...
・Capacitor, 20... Power supply, 21... Motor, 3
- Directional intermittent means, 32... Holding means, 33-3
6... Controllable intermittent means, 37... Driven means. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 0 Figure 3

Claims (1)

[Scope of Claims] Holding means that is excited by a power source and can hold a charge, voltage, or current, and when the power source is in operation, the voltage of the power source is transmitted to the holding means, and when the voltage of the power source drops, the power source and the holding means directional disconnection means for separating the M, and a disconnection path connected between one terminal side of the holding means and one terminal side of the driven means, the M being disconnected in response to a control input;
a controllable disconnecting means of l, and a disconnecting path is connected between the other terminal side of the holding means and the one terminal side of the driven means,
Intermittent control is performed in accordance with the first external control input and the power supply operation input, and when in the "continued" state, the first controllable intermittent means is controlled to be "off", and when in the "off" state. a second controllable disconnection means that controls the first controllable disconnection means to be in the "on"state; and a disconnection path between the one terminal side of the holding means and the other terminal of the driven means; a third controllable disconnection means that is connected and disconnects in response to a control input; a disconnection path is connected between the other terminal side of the holding means and the other terminal side of the driven means; Intermittent control is performed according to the input and the input from the holding means, and when in the "on" state, the third controllable on/off means is controlled to the "off" state, and when in the "off" state, the third controllable on/off means is controlled to the "off" state. and a fourth controllable intermittent means for controlling the third controllable intermittent means to a "continuous" state.