JP2005051932A - Power unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the breakage of a device and the breakage of a PWM control IC which is supplied with output voltage concerned as a feedback signal, by preventing such trouble that excessive voltage is supplied to the side of load. <P>SOLUTION: A power unit is equipped with a momentary power failure detecting circuit 2 which detects voltage change when primary input DC voltage causes the momentary power failure phenomena of momentary cutting, a PWM control circuit 4 which controls the converting action in a voltage converting circuit 1 by varying the pulse width when it detects the input DC voltage by means of the momentary power failure detecting circuit 2, and a MAX-Duty control circuit 7 which controls it so as to lower the variable upper limit value of the pulse width of the PWM control circuit 4 when the momentary power failure detecting circuit 2 detects the momentary power failure of input DC voltage. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the power supply device that adjusts the voltage generated by the DC power supply and supplies it to the outside, the present invention prevents abnormal boosting of the output side voltage when an instantaneous interruption occurs in the input voltage. The present invention relates to a power supply apparatus having a power supply interruption detection circuit that prevents damage.

  In recent years, for example, electronic devices using a dry battery as a power source such as a nickel-cadmium (NiCd) battery or a nickel-hydrogen (NiH) battery are generally used. Since these dry batteries have an output voltage in a relatively low region, the voltage that can be supplied by the dry battery and the voltage used in the electronic device do not always match. For this reason, a voltage conversion device called a DC / DC converter is used. In use, the power supply voltage is stably supplied to the electronic circuit by converting the output voltage of the dry battery.

  Here, a conventional step-up DCDC converter type power supply apparatus will be described with reference to FIGS. 14 and 15. FIG. In FIG. 14, when the input voltage Vb is given from the dry battery 149, it is converted into the output voltage Vo by the voltage conversion circuit 141 and supplied to the load circuit 147. The output voltage Vo is simultaneously supplied to the phase compensation error amplifier 142, subjected to phase compensation, and then supplied to the PWM control circuit 143. The PWM control circuit 143 generates a PWM signal by comparing this input with a signal from the triangular wave oscillation circuit 144. A predetermined output voltage Vo is obtained by turning on and off the switching transistor of the voltage conversion circuit 141 by this PWM signal and rectifying the output.

  Further, the PWM control circuit 143 controls the rush current limit at the start-up or the maximum output voltage limit at the transition by the soft start control circuit 145 and the MAX-Duty control circuit 146. Here, a specific example of the voltage conversion circuit 141 is shown in FIG. As an example, the operation of the boost converter of FIG. 15 will be described. The voltage conversion circuit shown in FIG. 15 is a configuration example of a boost converter that boosts and outputs an input voltage. In the voltage conversion circuit 141, the drain of the transistor Q151 is connected to the power supply terminal 151a via the choke coil L151, and the source is grounded. The gate is connected to a pulse input terminal 151b for receiving a switching pulse input from a PWM generation circuit (PWM: Pulse Width Modulation) (not shown).

  The node of the transistor Q151 and the choke coil L151 is connected to the anode of a diode (Schottky barrier diode) D151, the capacitor C151 is connected to the cathode of the diode D151, and the other end of the capacitor C151 is grounded. An output terminal 151c to the load circuit 147 and a feedback terminal 151d to the error amplifier (phase compensation type error amplifier) 142 in FIG. 15 are connected to the coupling point of the diode D151 and the capacitor C151. The transistor Q151 is an N-channel MOS-FET (Metal Oxide Semiconductor-Field Effect Transistor), and functions as a switching element by taking an ON / OFF state according to a switching pulse from the pulse input terminal 151d.

  When the transistor Q151 is switched from ON to OFF by this switching pulse, the excitation energy from the choke coil L151 is released at the connection point between the choke coil L151 and the diode D151, so that the voltage higher than the voltage of the power supply terminal 151a. Occurs and the capacitor C151 is charged. The voltage at this connection point gradually decreases thereafter, and when the transistor Q151 is turned on again, it becomes a voltage substantially equal to the ground voltage. Therefore, a voltage fluctuation in response to the switching pulse appears at the anode of the diode D151. When the fluctuation is rectified by the diode D151, a voltage higher than the input voltage is obtained. This voltage is smoothed by the capacitor C151, extracted from the output terminal 151c, and supplied to the load. The same voltage as that of the output terminal 151c is output from the feedback terminal 151d and supplied to the error amplifier (phase compensation type error amplifier) 142 of FIG. In the error amplifier (phase compensation type error amplifier) 142 of FIG. 15, the fluctuation of the voltage output from the feedback terminal 151d is amplified and further subjected to phase compensation, and then the triangular wave oscillation circuit 144 is executed by the PWM generation circuit 143 in the next stage. The level of the output is compared and a PWM signal is generated. The switching pulse output is controlled by this PWM signal.

  Further, in Patent Document 1, in order to prevent an overcurrent from flowing through the switching element when the input voltage suddenly rises, if a momentary interruption of the input AC voltage occurs, the comparison means includes a rectifier circuit in the period. Therefore, the comparison means does not generate a pulse, so that the pulse detection circuit cannot detect the pulse at this time and outputs a cutoff signal, and the pulse detection circuit delays the cutoff signal by about 20 msec. Since the output is interrupted, the interruption signal is output for about 20 msec after the momentary interruption is resolved, and when the interruption signal is input from the pulse detection circuit, the drive pulse generation circuit stops generating the drive pulse, and switching A power supply device that turns off an element is disclosed.

  Patent Document 2 discloses a start circuit for a DC / DC converter in order to prevent a sudden rise in the output voltage of the DC / DC converter due to a power supply interruption of the main power supply. A DC / DC converter start circuit is disclosed that restarts the soft start circuit when the voltage supplied to the primary side exceeds the reference voltage.

Japanese Patent Laid-Open No. 11-164548 JP-A-63-77375

  In a power supply device using a dry battery, the dry battery is generally housed in a battery holder, and power is supplied to a load via an electrode provided in the battery holder. At this time, in order to keep the contact resistance between the battery electrode and the holder-side electrode small, the holder-side electrode is usually brought into contact with the battery electrode while always applying a certain pressure by adopting a spring structure or a plate spring shape. It has a structure. In this case, when any vibration or shock is applied to the set, the contact with the battery electrode may be temporarily interrupted due to the vibration of the electrode. This phenomenon is called an instantaneous interruption phenomenon.

  When this phenomenon occurs during the operation of the power supply apparatus adopting the DC-DC converter format, the supply of UNREG voltage indicating the primary side input DC voltage of the DC-DC converter is momentarily interrupted, so that the PWM signal changes to full duty. Since the PWM signal is at full duty when the instantaneously interrupted UNREG voltage returns to the normal value, the output voltage is higher than the normal voltage (EX: about 200%). When this overvoltage exceeds the withstand voltage of the device connected to the load side, each device is damaged. Further, when this output voltage is directly connected to the error input pin of the PWM control IC, inconvenience such as destruction of the PWM control IC itself occurs.

  The present invention has been made in view of such problems. Even when the supply voltage from the dry battery is momentarily interrupted, the PWM signal change upper limit value (MAX-Duty) is forcibly lowered to make it excessive on the load side. An object of the present invention is to provide a power supply apparatus that prevents the supply of a voltage and prevents the destruction of a device connected to a load, and prevents the destruction of a PWM control IC supplied with the output voltage as a feedback signal. And

  Here, Patent Document 1 turns off the switching element when the input AC voltage is momentarily interrupted. Further, Patent Document 2 detects that the primary side input exceeds a specified level, and restarts the soft start circuit of the DC / DC converter. On the other hand, in the present invention, the output is not stopped as in Patent Document 1, but it is detected that the primary side input has fallen below the specified value, and the variable maximum value (MAX-Duty) of the PWM signal is detected. By lowering, the amount of overshoot that occurs when the primary side input next returns to a normal value is limited. Unlike the restart of soft start as in Patent Document 2, the rise time of the output voltage can be rapidly recovered in the case of MAX-Duty restriction.

  In order to solve the above-described problem, the power supply device of the present invention has an instantaneous interruption phenomenon detecting means for detecting a change in voltage when the primary side input DC voltage causes an instantaneous interruption phenomenon of minute time, and instantaneous interruption phenomenon detection. When the instantaneous interruption phenomenon of the input DC voltage is detected by the means, the pulse width control means for controlling the conversion operation in the voltage conversion means by changing the pulse width, and the instantaneous interruption phenomenon of the input DC voltage is detected by the instantaneous interruption phenomenon detection means. Variable upper limit control means for controlling so as to lower the variable upper limit of the pulse width of the pulse width control means when detected.

  For example, in a DC-DC converter type DC power supply that is supplied with power from a dry battery or the like through a battery holder, the occurrence of a momentary power interruption phenomenon caused by poor contact between the battery and the battery holder caused by vibrations of the device, etc. Sometimes, when the primary side input voltage falls below the limit voltage, the pulse width control signal shifts to full duty, and then when the input voltage returns to the normal value, an excessive output voltage is transiently output to the secondary side output. . As a result, an abnormal voltage to the secondary side output is generated, thereby causing destruction of the control IC and the load circuit of the pulse width control means.

  The present invention detects this instantaneous interruption phenomenon, and controls to reduce the variable upper limit value (MAX-Duty) of the pulse width control signal when the detection signal is used to control the switching operation of the DC-DC converter. Prevents overvoltage from occurring on the output side.

  According to the present invention, when it is detected by the instantaneous interruption phenomenon detecting means provided at the power supply terminal to the power supply device that the input voltage has reached less than the specified value, the ON / OFF circuit of the power supply device is set. By controlling, the power supply device is forced to transition to the OFF state, or the variable upper limit value (MAX-Duty) of the pulse width control signal is lowered to apply an excessive output voltage to the load. Or damage to the power supply control IC can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration example of a power supply device according to the present invention.
This power supply apparatus includes a DC power supply Vb that is a power supply source by the dry battery 10, a fuse Fu11 that protects the DC power supply Vb, a voltage conversion circuit 1 that converts an output voltage from the DC power supply Vb into a desired voltage Vo, and this voltage. The phase compensation error amplifier 3 that amplifies the fluctuation of the voltage Vo output from the conversion circuit 1 and performs phase compensation, and the output of the phase compensation error amplifier 3 and the output of the separately provided triangular wave oscillator 5 are compared. By receiving the PWM control circuit 4 for generating the PWM signal and the start signal output from the separately provided power supply SW9, the soft start control for starting the power supply apparatus and reducing the rush current at the start is performed. Circuit 6, a MAX-Duty control circuit 7 for limiting the upper limit of change of the PWM signal in order to suppress the generation of an excessive output voltage at start-up, Constituted by the momentary interruption phenomenon detection circuit 2 for detecting the interruption phenomenon.

[Instantaneous interruption phenomenon detection circuit]
Next, details of the instantaneous interruption phenomenon detection circuit will be described with reference to FIG.
An input voltage Vi is connected to the input terminal, and an input unit of the stabilized power supply 21 is further connected. This stabilized power supply 21 has a function of maintaining a stable output even if the input voltage Vi is momentarily fluctuated because a relatively large capacitor C1 is connected to the output section. Are connected to the power supply terminals of the comparator 22 and the second comparator 23 and supplied to the constant current source I1. Further, one end of a resistor R1 is connected to the input terminal. The other end of the resistor R1 is connected to one end of the resistor R2 and to the + input terminal of the comparator 22. The other end of the resistor R2 is grounded to GND. The negative input terminal of the comparator 22 is connected to the positive terminal of the reference power supply Vref1, and the other negative terminal of the reference power supply Vref1 is grounded. The output terminal of the comparator 22 is connected to the gate (Gate) of the Nch MOSFET Q1, and the source (Source) of Q1 is grounded. The drain (Drain) of Q1 is connected to the output terminal of the constant current source I1, is connected to one terminal of the capacitor C2, and is further connected to the negative input terminal of the comparator 23. The other terminal of C2 is grounded.

  The + input terminal of the comparator 23 is connected to the + side terminal of the reference power supply Vref2, and the other − side terminal of the reference power supply Vref2 is grounded. The output terminal of the comparator 23 is connected to the output terminal OUT-1 of the instantaneous interruption phenomenon detection circuit 2 in FIG. 1, and is connected to the PWM control circuit 4 or the MAX-Duty control circuit 7 in FIG.

  In the case of a circuit type in which the output terminal OUT-1 is connected to the MAX-Duty control circuit 7, when the aforementioned instantaneous interruption time is short, there may be a case where the duty limitation cannot be sufficiently applied. It is necessary to provide a circuit that extends the time for an appropriate time. This circuit will be described with reference to FIG. 3 and FIG. FIG. 3 shows an example in which an output signal duration extension circuit 31 is provided between the comparator 23 and the output terminal OUT-1. As shown in FIG. 4 as an example, the output signal duration extension circuit 31 includes a one-shot multivibrator 41 that maintains a state until the output signal from the comparator 23 becomes a trigger, an output signal from the comparator 23, and a one-shot multi-vibrator. This can be realized by a circuit configuration including an AND gate 42 that calculates a logical product with the output signal of the vibrator 41.

Next, details of the operation will be described with reference to FIGS. 2 to 4 and FIGS.
First, it is assumed that the Vin input voltage Vi shown in FIG. 5A appears due to the above-mentioned instantaneous interruption phenomenon, and an instantaneous interruption region 51 from the point A to the point B appears and drops below the voltage VS1 shown by the predetermined formula 1. Here, VS1 is a reference voltage defined by Equation 1.

(Formula 1)
VS1 = (R1 + R2) Vref1 / R2

  Then, the voltage drop portion is detected by the comparator 22, and a pulse as shown in FIG. 5B is obtained as the output of the comparator 22. Since the output of the comparator 22 is normally kept at the “high (H)” level output, both ends of C2 are short-circuited by Q1, but the negative pulse as shown in FIG. 5B is the gate (Gate) of Q1. Q1 is cut off and charging of C2 with a constant current defined by the constant current source I1 is started.

  As a result, a sawtooth wave as shown in FIG. 5C is generated at C2 {the negative input terminal of the comparator 23}. This sawtooth wave is compared with the reference power source Vref2 by the comparator 23, and a pulse as shown in FIG. 5D is obtained as its output (output inversion at point C). By supplying the pulse of FIG. 5D to the PWM control circuit 4 or the MAX-Duty control circuit 7 of FIG. 1, the PWM signal is forcibly stopped or the MAX-Duty limit value of the PWM signal is forcibly reduced. The above-mentioned effects can be obtained.

5E to 5F illustrate the operation of the power supply apparatus when the PWM signal is not forcibly stopped or the MAX-Duty limit value of the PWM signal is not forcibly reduced.
In this case, if a momentary interruption occurs between points A and B in FIG. 5A, the output voltage starts to gradually decrease because the input voltage suddenly decreases at point A, and the PWM signal receives feedback of the output voltage. Then, the duty is changed to the maximum value. Next, when the input voltage returns to the normal value at point B, the output voltage is much higher than the original set voltage (ex: about 200%) because the duty (duty) of the PWM signal is at the maximum value. Output voltage is generated.

Next, FIG. 5G illustrates an operation when the PWM signal is forcibly stopped.
In this case, when the input voltage suddenly drops at the point A, the detection pulses as shown in FIG. 5D are obtained by the above-described operations of the comparators 22 and 23, and this pulse is supplied to the PWM control circuit 4 to generate the PWM signal. Force stop. Therefore, the output of the power supply device is also stopped, and application of an excessive voltage to the load circuit 8 and the control IC of the PWM control circuit 4 can be prevented. Further, FIGS. 5H to 5I illustrate operations when processing for forcibly reducing the MAX-Duty limit value of the PWM signal is performed.

  In this case, when the input voltage suddenly drops at the point A, the detection pulses as shown in FIG. 5D are obtained by the above-described operations of the comparators 22 and 23, and this pulse is supplied to the MAX-Duty control circuit 7, whereby the PWM signal By forcibly reducing the MAX-Duty limit value, it is possible to minimize the amount of overshoot of the output voltage when the input voltage returns at point B. Therefore, control of the load circuit 8 and the PWM control circuit 4 is possible. Application of excessive voltage to the IC can be prevented.

  By the way, when the instantaneous interruption time is shorter than the response time of the PWM signal, only a slight output fluctuation is required. Therefore, if measures such as those of the present invention are taken, the output fluctuation may be increased. Using the circuit composed of Q1, I1, C2, Vref2, and the comparator 23, the pulse below the time (t) in Expression 2 defined by I1, C2, Vref2 is ignored.

(Formula 2)
T = CVref2 / I
However, C = C2 capacity, I = I1 current amount

  In addition, when the output pulse width of the comparator 23 is shorter than the response time of the PWM signal, an appropriate change may not be applied even if the limit value of MAX-Duty is changed. Such a problem is solved by adding a pulse having an appropriate fixed time. A configuration example of this countermeasure is shown in FIGS.

  FIG. 3 shows a circuit example in which an output signal duration extension circuit 31 is added to the output terminal of the comparator 23. FIG. 4 shows a specific embodiment of the output signal duration extension circuit. As shown in FIG. 4, the output of the comparator 23 is applied to one input of the ANDGate 42 and also applied to the input terminal of the one-shot multivibrator 41. On the other hand, when the output of the one-shot multivibrator 41 is applied to the other input terminal of the AND-Gate 42, a pulse with an expanded output pulse width of the comparator 23 can be obtained as shown in FIG. 7C. FIG. 6 shows an operation timing chart when an output signal duration extension circuit is added.

  Accordingly, when there is an output from the comparator 23 shown in FIG. 6A, an output of the extended duration of the output signal in which the extension time 61 shown in FIG. 6B is extended is output, and the MAX-Duty shown in FIG. 6C is limited. Since the duty-controlled PWM waveform is obtained, the output voltage fluctuation is suppressed when the limit is applied to the MAX-Duty shown in FIG. 6D. In this case, it is possible to prevent the occurrence of an excessive output voltage of the power supply apparatus when the input voltage is momentarily interrupted by the same operation as described above.

FIG. 8 is a circuit diagram showing details of the impact value detection type instantaneous interruption phenomenon detection circuit.
A resistance R1 and a resistance R2 connected to the + input terminal of the comparator 22 of the instantaneous interruption phenomenon detection circuit of FIG. Change to. FIG. 9 is a timing chart showing the operation of the impact value detection type instantaneous interruption phenomenon detection circuit. With this, when there is an impact input to the apparatus shown in FIG. 9A, the sensor output shown in FIG. 9B is output, and FIG. A sensor amplifier output is output, and a comparator output having a large impact value 93 that is greater than the small impact value 92 shown in FIG. 9D and exceeds the impact value detection standard boundary value 91 is output. The comparator output shown in FIG. 9C corresponds to the comparator output shown in FIG. 5D. The subsequent operation is the same as the operation after FIG. 5E.

[MAX-Duty restriction circuit]
An example of the configuration of the MAX-Duty restriction circuit is shown in FIG.
From FIG. 10, when the triangular wave 105 is applied to the input terminal E, it is amplified by the operational amplifier 102 and output to the point F. The amplification factor of the operational amplifier 102 is determined by the ratio of the resistor R12 and the resistor R11. During normal operation, the reference voltage Ref: A (Va) is input to the + input of the operational amplifier 102. Since the output of the instantaneous interruption phenomenon detection circuit 2 in FIG. 1 is at the “high (H)” level, as shown in FIG. 11B, the triangular wave 105 at the point F is an average DC potential set by the reference voltage Ref: A (Va). Is output in a state where it is superimposed on the + and is supplied to the + input terminal of the comparator 103 at the next stage. Since the error signal from the phase compensation type error amplifier 3 of FIG. 1 is input to the negative terminal of the comparator 103, the error signal is positioned at substantially the center of the triangular wave as shown in FIG. 11B in the stable state of the system. Thus, the output of the comparator 103 (PWM output) continues to operate at a duty 112 (Duty: Ds) during normal operation as shown in FIG. 11C.

  As shown in FIG. 11B, when the error signal variable range 111 is ΔVe, the lower limit DC level is Ve1, and the upper limit DC level is Ve2, when the error input becomes the lower limit Ve1, the PWM output is as shown in FIG. 11D. Similarly, the operation is performed at MAX-Duty: Da indicated by 113. Since the error input cannot fall below Ve1, the width of the PWM signal cannot be further increased. The duty at this time is Max-Duty.

  Here, assuming that the above-mentioned instantaneous interruption phenomenon has occurred, the instantaneous interruption phenomenon detection signal 106 is input to the point K in FIG. 10, and the switch SW1 is turned OFF and the switch SW2 is turned ON. The Ref applied to is switched to Ref: B. Since this Ref voltage is set in advance to Va> Vb, the signal at the point F, which is the output of the operational amplifier 102, has a triangular wave center DC potential lowered to Vb as shown in FIG. 11E. Since the UNREG input is momentarily interrupted, the error input to point H naturally goes down to the lower limit Ve1, so that the PWM output is as shown in FIG. 11F, and Duty: Db indicated by 116 is output. Since the DC bias point of the triangular wave is lowered, even if the same error level Ve1 as that in the normal operation is input to the comparator 103, Db116 in FIG. 11F becomes smaller than Da113 in FIG. 11D. That is, MAX-Duty is limited.

  As another method for limiting the MAX-Duty, there is a method in which a 3-input type comparator 121 shown in FIG. In FIG. 12, in the normal operation, the switch SW1 is turned on and the switch SW2 is turned off, and Vc and Vd are set in a relationship of Ve1> Vc and Ve1 <Vd with respect to the lower limit value Ve1 of the error input.

  During normal operation, Vc <Ve1, so the error input operates at the level 132 shown in FIG. 13A without being limited by Vc, and the error input shown in FIG. 11B corresponds to the PWM output at the center value according to the input. The PWM output of the duty Ds133 during normal operation is output. When the instantaneous interruption phenomenon occurs, the switch SW1 is turned off and the switch SW2 is turned on by the instantaneous interruption phenomenon detection signal 106 in FIG. However, since Vd> Ve1 is set and an input higher than the lower limit value of the error input is input to the same polarity input terminal of the comparator 103, the error input is ignored and the PWM output is compared with the voltage of Vd. The PWM output at the momentary interruption detection operation shown in FIG. 13C is output with a pulse width of MAX-Duty: Db indicated by 134. As a result, the duty is limited.

  The power supply apparatus according to the present invention can be applied to a case where a power supply voltage is supplied from a dry battery to a digital camera or portable camera-integrated video recorder as a portable electronic device.

It is a circuit diagram which shows an example of the power supply device by this invention. It is a circuit diagram which shows the detail of an instantaneous interruption phenomenon detection circuit. It is a figure which shows the example of a duration extension of the output signal of an instantaneous interruption phenomenon detection circuit. It is a figure which shows the specific example of the duration extension circuit of an output signal. FIG. 5A is the input voltage, FIG. 5B is the output of the comparator 22, FIG. 5C is the drain waveform of Q 1, FIG. 5D is the output of the comparator 23, and FIG. 5F shows output voltage fluctuation, FIG. 5G shows output voltage fluctuation when PWM is stopped, FIG. 5H shows PWM waveform when MAX-Duty is restricted, and FIG. 5I shows MAX-Duty with restriction. Output voltage fluctuation. FIG. 6A shows the output of the comparator 23, FIG. 6B shows the output of the output signal whose duration is extended, FIG. 6C shows the PWM waveform when the MAX-Duty is limited, and FIG. 6D shows the MAX-Duty. This is the output voltage fluctuation when a limit is applied to. 7A is a timing chart showing the operation of the output signal duration extension circuit, FIG. 7A shows the output of the comparator 23, FIG. 7B shows the output of the one-shot multivibrator 41, and FIG. 7C shows the output of the AND gate 42. It is a circuit diagram which shows the detail of an impact value detection type instantaneous interruption phenomenon detection circuit. FIG. 9A is a timing chart showing the operation of the impact value detection type instantaneous interruption phenomenon detection circuit, FIG. 9A is an impact input to the apparatus, FIG. 9B is a sensor output, FIG. 9C is a sensor amplifier output, and FIG. It is a circuit diagram which shows the detail of a MAX-Duty control circuit. 11A is a timing chart showing the operation of the MAX-Duty control circuit. FIG. 11A is an E point: triangular wave input, FIG. 11B is an F point: triangular wave output, FIG. 11C is a PWM output with an error input being a center value, and FIG. Is the PWM output at the minimum value (lower limit value), FIG. 11E is the F point: triangular wave output, and FIG. 11F is the PWM output at the momentary interruption detection operation. It is a circuit diagram which shows the detail of another MAX-Duty control circuit. 13A is a timing chart showing the operation of another MAX-Duty control circuit, FIG. 13A is a F point: triangular wave output, FIG. 11B is a PWM output with an error input at a center value, and FIG. 13C is a PWM output during an instantaneous interruption detection operation. is there. It is a circuit diagram which shows an example of the conventional power supply device. It is a circuit diagram which shows the structural example (boost type | mold) of a power supply converter circuit.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Voltage conversion circuit, 2 ... Instantaneous interruption phenomenon detection circuit, 3 ... Phase compensation type | mold error amplifier, 4 ... PWM control circuit, 5 ... Triangular wave oscillator, 6 ... Soft start control circuit, 7 ... MAX-Duty control circuit, 8 ... Load circuit, 9 ... power switch, 10 ... dry cell, 11 ... fuse, 21 ... stabilized power supply, 22 ... comparator, 23 ... comparator, 31 ... output signal duration extension circuit, 41 ... one-shot multivibrator, 42 ... AND gate , 81 ... Shock sensor, 82 ... Sensor amplifier, 101 ... Inverter, 102 ... Operational amplifier, 103 ... Comparator, 105 ... Triangular wave input, 106 ... Instantaneous interruption detection signal, 107 ... Error input, 108 ... PWM output

Claims (6)

In a DC-DC converter type power supply apparatus that converts a primary side input DC voltage into a secondary side output DC voltage by a voltage conversion means and outputs the converted voltage.
When the primary side input DC voltage causes a momentary disconnection phenomenon in a minute time, an instantaneous interruption phenomenon detection means for detecting the voltage change;
Pulse width control means for controlling the conversion operation in the voltage conversion means by varying the pulse width when the instantaneous interruption phenomenon detection means detects the instantaneous interruption phenomenon of the input DC voltage;
Variable upper limit control means for controlling the pulse width control means to lower the variable upper limit value of the pulse width when the instantaneous interruption phenomenon detection means detects the instantaneous interruption phenomenon of the input DC voltage;
A power supply device comprising: The power supply device according to claim 1, wherein
The instantaneous interruption phenomenon detection means includes a detection means for detecting a decrease in the level of the primary input DC voltage, a constant current integration circuit that starts operation by an output of an output stage of the detection means, and a first output of the integration output of the integration circuit. The second detection means for detecting the second level is provided, and only when there is an output of a certain pulse width or more, the output is regarded as a detection signal of the instantaneous interruption phenomenon, and the control signal is sent to the pulse width control means in the subsequent stage. A power supply device that outputs the power. The power supply device according to claim 2, wherein
The instantaneous interruption phenomenon detection means is provided with an output signal duration extension means at the output of the second detection means, so that even when a detection pulse with a short time width less than the minimum limit is output, a pulse width output exceeding the minimum limit is output. A power supply device characterized by being generated. The power supply device according to claim 1, wherein
The instantaneous interruption phenomenon detecting means detects an instantaneous interruption phenomenon between a holder side electrode in which a dry battery as a power source of a portable electronic device is stored and an electrode of the dry battery. The power supply device according to claim 1, wherein
The power interruption device characterized in that the instantaneous interruption phenomenon detecting means is incorporated in the DC-DC converter as an integrated circuit. The power supply device according to claim 1, wherein
The instantaneous interruption phenomenon detection means uses a shock sensor using a piezoelectric element or the like,
A power supply device that detects an instantaneous interruption phenomenon.

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