JPH033018A - Power supply device - Google Patents

Abstract

PURPOSE:To attain protection corresponding to respective outputs by providing the power supply device with the 1st protecting means for sending a protection signal nd the 2nd protection means for protecting the power supply device by the protection signal, sending a protection releasing signal to the 1st protection means and releasing the protection of the 2nd protection means to restart power supply. CONSTITUTION:The power supply device is provided with a detecting means I for detecting abnormality such as overcurrent, the 1st protection means II for sending a protection signal to protect the power supply device by the detecting means I and the 2nd protection means III for protecting the power supply device by the protection signal. Abnormality such as overcurrent or overvoltage is detected by the detecting means I, the 1st protection means II receiving the output sends a protection signal for protecting the power supply device to the power supply device and the 2nd protection means II receiving the protection signal protects the power supply device. A control means IV sends a protection releasing signal to the 1st protection means II to release the protection of the 2nd protection means II and restart the power supply. Consequently, the power supply device is protected, and when plural outputs are generated, protection corresponding to respective outputs can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a power supply device, and particularly to a protection circuit for a power supply device.

(Conventional Technique) Conventionally, a power supply bag N (hereinafter referred to as a device) has an active element that supplies power to a load, or a protection device that operates to prevent damage to the device when an overcurrent or overvoltage occurs in the load. It had a circuit.

(Problem to be Solved by the Invention) However, when the conventional example has a plurality of outputs, each of the plurality of outputs must be protected as described above to prevent the device from being destroyed. . For this reason, for example, it is necessary to provide a plurality of overcurrent detection circuits in the power supply device, and protection must be provided corresponding to each different output.

In addition, if it is necessary to maintain the output down until the specified output occurs again after detecting an abnormality and protecting the power supply as in the conventional example, a capacitor or Schmitt trigger circuit may be used. A time constant circuit is required.

As a result of the above, there have been problems such as the circuitry in the power supply device becoming complicated, resulting in poor reliability, and the device becoming larger and higher in cost.

This invention was made in order to solve the problems of the conventional example as described above, and it protects the power supply when an abnormality such as overcurrent or overvoltage occurs in the power supply, and also protects the power supply according to the output. The purpose of the present invention is to provide a power supply device that can change the state of the power supply and, in the case of multiple outputs, provide protection according to each output.

[Means to solve the problem]

Therefore, in the present invention, in the power supply device, a detection means (I) for detecting an abnormality such as overcurrent or overvoltage is provided.
and a first protection means (II) that sends a protection signal for protecting the power supply device based on the output of the detection means (I), and a second protection means (III) that protects the power supply device using the protection signal. and a control means (IV) for sending a release signal of the protection to the first protection means (I), canceling the protection of the second protection means (m), and restarting the power supply.
The purpose of the present invention is to achieve the above object.

In the power supply device, the control means (rV) monitors the state of the first protection means (II), and when detecting a protection state, maintains the protection state for a predetermined time, generates a protection release signal, and restarts the power supply. The above object is achieved by being a means for starting the power supply, and the detection means (1) in the power supply device is a means for detecting a plurality of abnormalities, and the control means (rV) is a means for detecting a plurality of abnormalities. This object is achieved by generating a release signal after holding the output of each detection means (I) for a predetermined time.

(Function) In the power supply device of the present invention, the detection means (I) detects an abnormality such as overcurrent or overvoltage, and the first protection means (II) that receives the output from the detection means (I) protects the power supply device. The second protection means (III) that receives the protection signal protects the power supply device. In addition, 5 control means (
IV) sends a protection release signal to the first protection means (n),
Release the protection of the second protection means (III) and restart the power supply.

The power supply device monitors the state of the first protection means (n) using the control means (rV), and when it detects a state in which protection is being performed, the power supply device maintains the protection state for a preset predetermined time and then
Generates a protection release signal and restarts the power supply.

Further, the power supply device has a detection means (I) that detects a plurality of abnormalities, and a control means (IV) that detects each of the detection means (4).
After holding for a predetermined time according to the output of , a release signal is generated,
Restart the power supply.

〔Example〕

Hereinafter, three embodiments of the present invention will be described based on the drawings.

(1) First, a first embodiment of the present invention will be explained using FIGS. 1 and 2.

FIG. 1 is a circuit diagram showing the sequence of a power supply device according to a first embodiment of the present invention, and FIG. 2 is an operating waveform diagram of this first embodiment. In FIG. 1, Dl rectifies line human power. A rectifier diode, C9 is a diode D, a capacitor that smoothes the output of the diode, T1 is a converter transformer, Ql is a switching element such as a power MO5FET, T3 is a detection transformer that detects the current flowing through the switching element (FET) Q+, and Dl is a converter. A rectifier diode that rectifies the secondary output of the transformer TI, C2 is a capacitor that smoothes the output of diode D2, 1 is a power supply device that constitutes a flyback switching regulator, and 2 is an overcurrent detector that is normally used. The circuit 3 receives the output from the overcurrent detection circuit 2 and sends a protection signal to the PWM circuit 5.
4 is a register that controls the M circuit 5; 4 is a CPU that sends a protection release signal for the power supply device to the register 3 to restart the power supply; and 5 is a converter transformer T, which outputs the desired secondary side output. The drive circuit 6 is a PWM circuit that generates a pulse signal to obtain a voltage, uses the pulse signal to drive the switching element Q1, and generates a voltage-converted output to the secondary winding of the converter transformer T1. , the detection means (I) is composed of a detection transformer T3 that detects the current flowing between the source trains of the switching element Q according to the secondary side load, and an overcurrent detection circuit 2, and detects abnormalities such as overcurrent or overvoltage. The first protection means (II) is composed of a register 3, and means for sending a protection signal for protecting the 7ttjf9j device 1 to the PWM circuit 5 based on the output from the over-Iff, tfL detection circuit 2. and the second protection means (m
) is one stage that is composed of a PWM circuit 5, a drive circuit 6 that drives the switching element Ql, and a switching element Q, and protects the power supply device by a protection signal from the register 3, and the control means (TV) is controlled by the CPU 4. It consists of
A protection release signal is sent to the register 3, and the second protection means (m
) is a means of canceling the protection and controlling the restart of the power supply.

Next, in Fig. 2, 2a is the output waveform of the overcurrent detection circuit 2, H
i is the output during the overcurrent detection period, Lo is the output of the normal current, 2
2c is a waveform outputted from the register 3;

Next, the operation of this first embodiment will be explained using FIGS. 1 and 2. In Figure 1, when outputting in a normal state, the pulse signal to obtain the desired secondary output is PWM.
The drive circuit 6 generated by the circuit 5 and receiving the pulse signal drives the switching element Q1 to generate a voltage-converted output to the secondary winding of the converter transformer T, which is rectified by the rectifier diode D2 and connected to the capacitor. It is smoothed by C2 and power is supplied to the load.

The above is a normal state, but detection when an abnormality occurs will be described with a focus on the detection means (I).

If an abnormality occurs on the secondary side, such as a short circuit or an overload, an excessive current flows between the drain and source of the switching element Q1 connected to the primary side of the converter transformer T1. This current is input to an overcurrent detection circuit (hereinafter referred to as M circuit) via a detection transformer T, and the M circuit detects an overcurrent.

As described above, regarding the protection of the power supply and the cancellation of the protection when an overcurrent is detected in the M circuit, the first protection means (n) and the second protection means (I [ The explanation will focus on l).

In FIGS. 1 and 2 of the drawings, when the M circuit detects an overcurrent, the M circuit 2 causes the register 3 to output H as shown in FIG. 28.
Outputs the protection signal of i. This output sets the register 3 and outputs the Hi signal shown in FIG. .

At this time, as shown in FIG. 2B, the CPU 4 always oscillates a clock with a constant period and inputs it to the register 3 manually. The set signal 2a of the register 3 in the surface M circuit 2 is Hi
After the output signal 2c becomes Lo, the output signal 2c of the register becomes Lo due to the CPU's manual signal 2b. As shown above, this signal causes the PWM circuit 5 to generate a PWM output again, and the FE
The TQI is driven and the power supply protection is released.

(2) Next, a second embodiment of the present invention will be described using FIGS. 3 to 5.

FIG. 3 is a circuit diagram showing the sequence of the second embodiment of the present invention, FIG. 4 is an operation waveform diagram of this second embodiment, and FIG. 5 is a flowchart for controlling the release operation of this second embodiment. In FIG. 3, the output of the register, which is the first protection means (II), is connected to the human power of the CPU 4, which is the control means (rV), and the CPU 4 is configured to monitor the state of the register 3 at regular intervals. has been done.

The rest of the configuration is the same as that of the first embodiment (FIG. 1), so redundant explanation will be omitted.

Next, in FIG. 4, a waveform 5a is the output of the overcurrent detection circuit 2 of the detection means (I), and its operation is the same as in the first embodiment. Also, based on this output, the register 3, which is the second protection means (n), controls the PWM output of the PWM circuit 5, as in the first embodiment. in this case,
The CPL 14 of the control means (IV) monitors the state of the register 3 by checking the manual boat l+ at regular intervals as shown in the waveform 5b of FIG. After holding, the clock is output from the output port O2 to the register 3, thereby controlling to reliably restart the output after stopping the output for a certain period of time α or more. Waveform 5C is the output waveform of register 3 at this time.

Next, the protection release operation control of this second embodiment will be briefly explained using FIG. 5.

In FIG. 5, the start is started, and in step 6a, the register is monitored to see if it is protected. If it is protected, it proceeds to step 6b, waits for a predetermined time α to elapse, and then proceeds to step 6C. The process proceeds to step 6C, where a protection release signal is sent to the register and the process ends.

(3) Next, a third embodiment of the present invention will be described using FIGS. 6 to 8.

FIG. 6 is a circuit diagram showing the sequence of the third embodiment of the present invention, FIG. 7 is an operation waveform diagram of this third embodiment, and FIG. 8 is a flowchart for controlling the operation of this third embodiment.
In FIG. 6, T1 has a plurality of output windings on the secondary side, for example, two windings form output 1 and output 2. in this case,
For example, if this power supply is used for a copying machine, output 1 is a high voltage output that generates several V, and output 2 is 5V to 2V.
Low voltage output is about 4V.

D2. C2, D3, and C3 are each output! .

A rectifier diode and a capacitor that rectify and smooth the output 2. R, is a detection resistor that detects the current supplied from the output 1, and is connected to the overcurrent detection circuit 2B, and the output of the overcurrent detection circuit 2B is connected to the register 3 and the CPU 4. Similarly, R2 is a current detection resistor of output 2, which is connected to the overcurrent detection circuit 2C, and whose output is connected to the resistor 3 and CPLI4. The rest of the configuration is the same as that of the second embodiment, so a description thereof will be omitted.

In the above configuration, the detection means (1) consists of a transformer T3 and overcurrent detection circuits 2A and 28.2C, the first protection means (II) is the register 3, and the second protection means (m) is the PWM circuit 5. and drive circuit 6 and switching element Q1
The control means (■) is the CPU 4. Next, the seventh
In the figure, waveforms 8a, 8b, and 8c represent the outputs of overcurrent detection circuits 2A, 2B, and 2C, respectively, and waveform 8d represents the output of the CPU 4.
Overcurrent detection circuit 2A input to.

2B, 2C, and a fixed period for monitoring the outputs of register 3.

Next, the operation of this third embodiment will be explained with reference to FIGS. 6 to 8, focusing on the control means (rV).

In FIG. 6, it is assumed that an overcurrent flows through output 1. As a result, the output of the overcurrent detection circuit 2B becomes Hi, which is input to the register 3, and the register 3 controls the PWM circuit 5. At this time, the CPU 4 confirms that the output of the register 3 is Hi at the timing shown by waveform 8d in FIG. 7, and also confirms that the output of the overcurrent control circuit 2B is Hi. After holding α for a predetermined time according to the program, the CPU 4 clocks the register and restarts.

Furthermore, if an overcurrent flows through the output 2 or the transformer T3, the company will restart the cpυ4 after holding β for a predetermined time.

Next, the release operation control of this third embodiment will be briefly explained using FIG. 8. After starting, the register monitors whether protection is applied by checking the manual boat 11 in step 9a, and if protection is applied, the process proceeds to step 9b and checks whether the output is from the overcurrent detection circuit (M circuit) 2B. It is determined by checking the human powered boat 12, and if the output is 2B, the process advances to step 9c, waits for a predetermined time α to elapse, and when α time has elapsed, a protection release signal is sent to the register from the output boat O6 in step 9d. send.

If it is not the output of the circuit 2B in step 9b, the process proceeds to step 9e, and in step 9e it is determined whether the output is the M circuit 2a or 2C by checking the manual boats 13, 14, and if it is the output of 2a or 2C, the process proceeds to step 9f. Wait for the predetermined time β to elapse, then proceed to step 9
Proceed to step d. Further, in step 9e, M circuit 2a or 2
If it is not the output of c, the process returns to step 9a. This third
In the example, especially since the output 1 is high voltage as mentioned above,
The predetermined time α between protection and restart must be an intermittent oscillation that is longer than the normal protection time. Furthermore, since the output 2 is a low voltage output, the predetermined time β from protection to restart may be short. That is, by using the present invention, power supply protection can be performed according to the output.

(Effects of the Invention) As explained above, according to the present invention, a power supply device includes a detection means (I) that detects abnormalities such as overcurrent or overvoltage, and a detection means (I) that protects the power supply device. It has a first protection means (■) that sends protection (No. 3) and a second protection means (I [I) that protects the power supply device with a protection signal, and sends a protection release signal to the first protection means (n). By providing a control means (rV) that sends the power, cancels the protection of the second protection means (III), and restarts the power supply,
Alternatively, in the power supply device, the control means (IV) monitors the state of the first protection means (■), and if it detects a state in which protection is applied, the control means (IV) maintains the protection state for a preset predetermined time and then releases the protection. By being a means for generating a signal and restarting the power supply, or in the power supply device,
The detection means (1) is a means for detecting a plurality of abnormalities,
The control means (IV) protects the power supply device by generating a release signal after holding the output of each detection means (I) for a predetermined time according to the output voltage, etc. This has the effect of providing a power supply device that can change the predetermined time period and, in the case of multiple outputs, provide protection according to each output.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a power supply device according to a first embodiment of the present invention, Fig. 2 is an operation waveform diagram of the first embodiment, Fig. 3 is a circuit diagram of a second embodiment of the invention, and Fig. 4 is an operation waveform diagram of the second embodiment, FIG. 5 is a flowchart for controlling the release operation of the second embodiment, FIG. 6 is a circuit diagram of the third embodiment of the present invention, and FIG.
The figure is an operation waveform diagram of the third embodiment, and FIG. 8 is a flowchart for controlling the release operation of the third embodiment. (I) -------Detection means (II) -...First protection means (Ol)...
--Second protection means (TV) --Control means Q+"" --Switching element T, --Converter transformer T3-1 --Detection transformer --Power supply device 2. 2A, 2B, 2C --- Overcurrent detection circuit 3・
...Register 4 ---CPU 5 ---PWM circuit 6 ---Drive circuit α, β --- Exposed to C31 for a predetermined period of time iiJ's first reward 乍'Jξ
"Narito" Figure 2

Claims (3)

[Claims] (1) a detection means for detecting an abnormal condition such as overcurrent or overvoltage; a first protection means for sending a protection signal to protect the power supply device based on the output of the detection means; and a first protection means for protecting the power supply device using the protection signal. and a control means for sending a protection release signal to the first protection means, releasing the protection of the second protection means, and restarting the power supply. power supply. (2) the control means monitors the state of the first protection means;
Claim 1 characterized in that, when a protected state is detected, the protected state is maintained for a preset predetermined period of time, and then a protection release signal is generated and the power is restarted. Power supply listed. (3) The detection means is a means for detecting a plurality of abnormalities, and the control means is a means for generating a release signal after holding the output for a predetermined time according to the output of each of the detection means. The power supply device according to claim 1 or 2.