JP2011172426A - Power supply apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply apparatus which provides a stable output power in correspondence to the fluctuation of a load while suppressing an increase in the number of components, such as a dummy resistance and a switch circuit, and in wiring space for connecting the components. <P>SOLUTION: The power supply apparatus includes: a load 1 including a plurality of light sources; a DC-DC converter 2 which adjusts a voltage to the load 1; a smoothing circuit 3 which is connected between the DC-DC converter 2 and the load 1 and supplies a smoothed output current to the load 1; a dummy resistance 4 which adjusts an output current supplied from the smoothing circuit 3; a switch circuit 5 disposed between the smoothing circuit 3 and the dummy resistance 4; and a controller 5 which controls drive of the load 1 and carries out control to establish and break connection between the smoothing circuit 3 and the dummy resistance 4 using the switch circuit 5 according to an output current to the load 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply device using a DC-DC converter for supplying a stable power supply, and is suitable, for example, as a power supply device for supplying a stable power supply to a load circuit constituting a vehicle meter.

  Conventionally, there is a power supply device using a DC-DC converter, which is disclosed in Patent Document 1, for example. The power supply apparatus according to the present invention is a power supply apparatus provided with a forward type DC-DC converter, and includes a dummy resistor and a dummy resistor that branch and output the output to a secondary circuit that is output by smoothing with an inductance and a capacitor. The power supply control means for controlling the connection between the switch circuit for turning on and off the connection and the dummy resistor is provided. With this configuration, it is possible to prevent an abnormal increase in the output voltage from the DC-DC converter by switching connection / disconnection to the dummy resistor according to the state of the load.

  Also, by providing a plurality of dummy resistors and switch circuits and selectively connecting the dummy resistor circuit corresponding to the amount of current from the secondary circuit to the load, an appropriate voltage value can be obtained when the output voltage rises abnormally. It is disclosed to suppress and control the increase in output voltage so that

JP-A-6-311748

  However, the provision of a plurality of these dummy resistors and switch circuits has a problem that the number of parts increases. Further, when the load resolution is high, the number of circuits further increases, so that not only the number of components but also a space on the circuit board for mounting these components is required, which is a problem.

  Further, in the circuit board, there is a problem that the wiring space of the control line from the power supply control means for controlling switching of energization / cutoff to the dummy resistor increases as the number of circuits increases.

  Accordingly, the object of the present invention is made by paying attention to the above-mentioned problems, and it is possible to change the load while suppressing the number of parts such as dummy resistors and switch circuits and the wiring space for connecting them. It is an object of the present invention to provide a power supply device that can obtain a stable output voltage.

  The power supply device of the present invention includes a load including a plurality of light sources, a DC-DC converter for adjusting a voltage to the load, and a smoothed voltage connected between the DC-DC converter and the load. A smoothing circuit to be supplied to the load, a dummy resistor for adjusting an output current supplied from the smoothing circuit, a switch circuit provided between the smoothing circuit and the dummy resistor, and controlling the driving of the load, Control means for performing control to switch the connection / disconnection between the smoothing circuit and the dummy resistor using the switch circuit in accordance with an output current to the load. .

  The control means adjusts an output current supplied from the smoothing circuit to the dummy resistor by performing pulse width modulation control on the switch circuit.

  Further, the control means controls the switch circuit so that an output current flows from the smoothing circuit to the dummy resistor when the light source is turned off.

  Further, the control means performs control for prompting start / stop of the DC-DC converter, and when switching the start / stop of the DC-DC converter, an output current flows from the smoothing circuit to the dummy resistor. Thus, the switch circuit is controlled.

  The present invention relates to a power supply device using a DC-DC converter, and suppresses the number of components such as dummy resistors and switch circuits and the wiring space for connecting them, and provides a stable output voltage corresponding to load fluctuations. Obtainable.

The figure which shows the structure in embodiment of this invention. The figure which shows each output current value according to the light source lighting number in embodiment same as the above.

  Embodiments to which the present invention is applied will be described below with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a circuit configuration of a power supply circuit of a vehicle meter, and includes a load 1, a DC-DC converter 2, a smoothing circuit 3, a dummy resistor 4, a switch circuit 5, a control means 6, A load driving circuit 7 is provided on the circuit board.

  In this case, the load 1 includes a plurality of light sources composed of light emitting diodes. The load 1 is connected to the control means 6 via the load drive circuit 7 so that each light source is independently turned on or off, and each light source is controlled based on a control signal from the control means 6. Configured to be controlled.

  The DC-DC converter 2 receives power from an in-vehicle battery or the like, generates a predetermined voltage, and outputs it to the load 1 via the smoothing circuit 3. Further, the DC-DC converter 2 is provided with an input port for inputting a signal from the control means 6, and starts or stops based on the signal from the control means 6.

  The smoothing circuit 3 is provided between the DC-DC converter 2 and the load 1 and is rectified and smoothed by connecting a diode D, an inductance L, and a capacitor C as shown in FIG. Supply output to load.

  The dummy resistor 4 is branched from the smoothing circuit 3 and connected via the switch circuit 5, and is provided with a resistance value selected according to the maximum current consumption of the load. The dummy resistor 4 can adjust the output current supplied from the smoothing circuit 3.

  The switch circuit 5 can be a transistor, and is connected between the smoothing circuit 3 and the dummy resistor 4, and determines whether or not there is an output from the smoothing circuit 3 to the dummy resistor 4 according to the control from the control means 6. Can be switched.

  The control means 6 can be a microcomputer. In this case, vehicle information (not shown) and a signal from a start switch (for example, an ignition switch) S are input, and the DC-DC converter 2 is started in accordance with the calculation of a predetermined program. / Stop, or the lighting / extinguishing of the load 1 is controlled via the load driving circuit 7. In this case, the control means 6 controls the load 1 so that many light sources are turned on as the value increases based on the vehicle information (for example, vehicle travel speed).

  Further, when all the light sources are turned off, the control means 6 performs pulse width modulation control on the switch circuit 5 using a signal of a duty ratio for encouraging a large output current to flow to the dummy resistor 4, so that there are many light sources. The switch circuit 5 is subjected to pulse width modulation control so that the output current flowing to the dummy resistor 4 becomes smaller as the output current flowing to the load 1 increases. In this case, as shown in FIG. 2, the output current Y to the dummy resistor 4 is adjusted in accordance with the output current X to the load 1 so that the total fluctuation current Zd of the total output current Z is small. ing. Therefore, since the rapid fluctuation of the output current from the smoothing circuit 3 can be suppressed, a stable output with good responsiveness can be obtained. Moreover, a stable power supply can be efficiently generated by suppressing a change in the amount of current from the DC-DC converter 2.

  The load drive circuit 7 is composed of a transistor, a resistor, or the like (not shown) connected between the load 1 and the control means 6, and is a switching means for selectively turning on / off the light source based on the control signal from the control means 6. It is.

  Next, the control by the control means 6 when starting the vehicle meter will be described.

  Based on the start switch S, the control means 6 first controls the switch circuit 5 so that it can be output from the smoothing circuit 3 to the dummy resistor 4 when the vehicle instrument shifts from the stopped state to the activated state. I do.

  Next, the control means 6 performs a starting process for outputting a signal prompting the DC-DC converter 2 to start to the DC-DC converter 2.

  Next, the control means 6 performs a vehicle information display process for generating a control signal for controlling lighting / extinguishing of the load 1 based on the input of the vehicle information and outputting it to the load drive circuit 7. In the vehicle information display process, the duty ratio is adjusted for the signal to the switch circuit 5 according to the output current to the load 1 (the number of light sources turned on), and the dummy resistor 4 increases as the output current to the load 1 increases. This is performed with pulse width modulation control for reducing the current flowing to the.

  By controlling according to these control procedures, immediately after the DC-DC converter 2 is started, even if the load 1 is in a no-load state (all the light sources are turned off), an output current flows to the dummy resistor 4 to the load 1 side. The configuration is such that no output current flows. Therefore, even when the vehicle information changes suddenly and the number of light sources to light changes, the difference in output current from the smoothing circuit can be narrowed, so that the power supply that can perform stable output with high responsiveness It becomes a device.

  Next, the control by the control means 6 until the vehicle instrument is finished and stopped will be described.

  Based on the start switch S, the control means 6 first generates a control signal for controlling the extinction of the load 1 and outputs it to the load drive circuit 7 when the vehicular instrument shifts from the operating state to the stopped state. Car information display processing is performed. In the vehicle information display process, the duty ratio is adjusted for the signal to the switch circuit 5 in accordance with the output current to the load 1 (the number of light sources turned on), and the dummy resistor 4 increases as the output current to the load 1 decreases. This is performed with pulse width modulation control for increasing the current flowing to the.

  Next, the control means 6 performs a stop process for outputting a signal prompting the DC-DC converter 2 to stop to the DC-DC converter 2.

  By controlling according to these control procedures, when the DC-DC converter 2 is stopped, even if the load 1 is in a no-load state (all the light sources are turned off), an output current flows to the dummy resistor 4 to the load 1 side. The configuration is such that no output current flows. Further, since the charge of the capacitor C can be discharged to the dummy resistor 4 side after the DC-DC converter 2 is stopped, it is possible to prevent the charge from flowing into the load 1 and malfunctioning.

  Such a power supply device is connected and smoothed by a load 1 including a plurality of light sources, a DC-DC converter 2 for adjusting a voltage to the load 1, and the DC-DC converter 2 and the load 1. A smoothing circuit 3 for supplying an output to the load; a dummy resistor 4 for adjusting an output current supplied from the smoothing circuit 3; a switch circuit 5 provided between the smoothing circuit 3 and the dummy resistor 4; Control means 5 for controlling the driving of the smoothing circuit 3 and the dummy resistor 4 to switch between connection / disconnection using the switch circuit 5 according to the output current to the load 1; It is equipped with.

  The control unit 6 adjusts the output current supplied from the smoothing circuit 3 to the dummy resistor 4 by performing pulse width modulation control on the switch circuit 5.

  Therefore, on the circuit board for mounting electronic components, a stable output voltage is obtained in response to load fluctuations while suppressing the number of components such as dummy resistors and switch circuits and the wiring space for connecting them. It is possible to provide a power supply device that can

  Further, the control means 6 controls the switch circuit 5 so that the output current flows from the smoothing circuit 3 to the dummy resistor 4 when the light source is turned off, so that the output current from the DC-DC converter 2 is controlled. The fluctuation range can be reduced, and the output current can be generated efficiently. In addition, since sudden fluctuations in output current can be reduced, abnormal output can be prevented.

  Further, the control means 6 performs control for prompting the start / stop of the DC-DC converter 2 and an output current flows from the smoothing circuit 3 to the dummy resistor 4 when switching the start / stop of the DC-DC converter 2. As described above, by controlling the switch circuit 5, when the DC-DC converter 2 is activated, the generation of abnormal output current can be suppressed to prevent the electronic components from being damaged, and the DC-DC converter 2 In the stopped state, problems due to the charge of the capacitor C can be prevented.

  Although the present invention has been described by way of example in the configuration of the above-described embodiment, the present invention is not limited to this, and various other configurations can be used without departing from the spirit of the present invention. Of course, it is possible to improve the design and change the design.

  The present invention relates to a power supply device using a DC-DC converter, and can be applied as, for example, a power supply device mounted on a moving body including an automobile, a motorcycle, an agricultural machine, or a construction machine.

DESCRIPTION OF SYMBOLS 1 Load 2 DC-DC converter 3 Smoothing circuit 4 Dummy resistor 5 Switch circuit 6 Control means

Claims (4)

A load including a plurality of light sources;
A DC-DC converter for adjusting the voltage to the load;
A smoothing circuit connected between the DC-DC converter and the load and supplying a smoothed voltage to the load;
A dummy resistor for adjusting the output current supplied from the smoothing circuit;
A switch circuit provided between the smoothing circuit and the dummy resistor;
Controlling the driving of the load;
Control means for performing control for urging to switch connection / disconnection between the smoothing circuit and the dummy resistor using the switch circuit according to an output current to the load;
A power supply device comprising: 2. The power supply device according to claim 1, wherein the control unit adjusts an output current supplied from the smoothing circuit to the dummy resistor by performing pulse width modulation control on the switch circuit. . 2. The power supply device according to claim 1, wherein the control unit controls the switch circuit so that an output current flows from the smoothing circuit to the dummy resistor when the light source is turned off. The control means performs control for prompting start / stop of the DC-DC converter,
2. The power supply device according to claim 1, wherein when switching the start-up / stop of the DC-DC converter, the switch circuit is controlled so that an output current flows from the smoothing circuit to the dummy resistor.

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