JP2008131838A - Power supply - Google Patents

Abstract

In a conventional power supply device, when a lighting voltage when a plurality of LEDs are connected in series becomes higher than a voltage that can be output by a DC-DC converter, a plurality of converters are prepared and the number of LEDs is allocated to each converter. There was a problem such as an increase in cost.
According to the present invention, in a booster circuit that boosts a power supply voltage, a positive power supply unit that performs a boosting operation in a positive potential direction on the input voltage side with respect to the DC-DC converter unit on the basis of the input voltage. The ground side is connected to a negative power supply unit that performs a boosting operation in the negative potential direction with reference to the ground voltage, and a load is applied with a differential voltage between the output of the positive power supply unit and the output of the negative power supply unit. By using a power supply device that boosts the output voltage as the driving configuration, the problem is solved as an efficient booster circuit can be obtained.
[Selection] Figure 2

Description

  The present invention relates to the configuration of a power supply apparatus when it is desired to light a large number of LED lamps in an environment where the power supply voltage is relatively low, such as an automobile, and more specifically, compared to a conventional DC-DC converter. Thus, the present invention relates to a configuration of the converter that can generate a voltage that is approximately twice as high and that can increase the input voltage to obtain an output voltage.

  FIG. 3 shows an example of the configuration of a power supply device 90 having a conventional positive power supply 80 and negative power supply 70. The voltage supplied from the power supply (V2) is converted into a control circuit 81, a coil 82, an FET 83, and A DC-DC converter circuit constituted by the diode 84 is used to boost the voltage to an appropriate voltage in consideration of the number of LEDs 60 to be connected in series, and a positive power supply 80 is obtained.

  At this time, the output voltage is divided by the resistors 85 and 86 and fed back to the control circuit 81 so that the output voltage does not fluctuate, so that the output voltage on the positive power supply 80 side is stabilized. This is effective for stabilizing the output voltage of the negative power supply 70 (charge pump circuit 71) described later.

  The DC-DC converter circuit described above, that is, the output voltage from the positive power source 80 is inverted by the charge pump circuit 71, and the polarity is inverted at substantially the same voltage as that obtained by the positive power source 80. Then, the LED 60 is connected and driven between the output of the positive power source 80 and the output of the negative power source 70 (charge pump).

By doing so, approximately twice the voltage can be obtained between the positive power source 80 and the negative power source 70. For example, when it is necessary to turn on a large number of LEDs 60 such as taillights at the same time. Advantages such as being able to cope without preparing two power supply devices can be obtained, and the cost can be reduced. A constant current circuit 61 is provided between the positive power source 80 and the negative power source 70 to make the current flowing through the LED 60 connected therebetween constant.
JP 2005-136157 A

  However, the power supply device 90 described above certainly doubles the output voltage and doubles the number of LEDs 60 that can be lit in series. However, the negative power supply 70 is a charge pump circuit 71, and the positive power supply 80 Therefore, the total output power does not exceed the output capability of the DC-DC converter described above. In addition, a large amount of current cannot be passed, and the boosted output includes the input voltage and is wasted.

  Therefore, if the LED 60 has a light emitting area twice to make it twice as bright, the output capability of the DC-DC converter must also be doubled. As a result, when used in a vehicular lamp using a recent LED 60 that requires more brightness as a light source, there is a problem that power supply capability is likely to be insufficient.

  Therefore, when supplying power exceeding the output capability of the DC-DC converter, it is necessary to prepare a plurality of the DC-DC converters, and to receive the LEDs 60 in a power range that can be lit. Accordingly, a disconnection detection circuit, a constant current circuit, and the like for the LED 60 are required according to the number of the DC-DC converters prepared, and it is necessary to centralize and monitor signals from those circuits. There was also a problem that the image could easily be raised. Further, the input voltage is included in the output voltage.

  As a specific means for solving the above-described conventional problems, the present invention provides a booster circuit for boosting a power supply voltage, with respect to the DC-DC converter unit, on the input voltage side, with this input voltage as a reference. A positive power supply unit that performs a boosting operation in the positive potential direction and a negative power supply unit that performs a boosting operation in the negative potential direction with reference to the ground voltage are connected to the ground side, and the output of the positive power supply unit and the negative power supply unit As a configuration for driving the load with the differential voltage between the output of the power supply device and the power supply device characterized by boosting the output voltage, and when providing a protection circuit between the positive power supply unit and the negative power supply unit, The problem is solved by using this power supply device provided in both power supply units.

  According to the present invention, a positive power supply unit and a negative power supply unit are connected to a positive power supply unit and a negative power supply unit on the input voltage side, and a load is driven between the output voltages of both. In the synchronized state, the positive power supply side boosts the input voltage to the positive side, the negative power supply side boosts the input voltage to the negative side, and in addition, the power supply voltage is between the positive and negative power supply parts. As a result, the total number of power supply units installed in vehicles can be reduced, and the cost can be reduced. Furthermore, the input voltage is the same as the conventional positive power supply voltage + negative power supply voltage. It will be able to output by raising the minutes.

  Below, this invention is demonstrated in detail based on embodiment shown in a figure. 1 is a block diagram showing the configuration of the power supply device 1 according to the present invention, and FIG. 2 is a circuit diagram showing the main part.

  First, the configuration of the power supply device 1 according to the present invention will be described with reference to FIG. 1. First, one terminal of a main part of the DC-DC converter unit 2 has a DC12V which is a power supply voltage of a normal vehicle such as a passenger car. Is applied via the input terminal Vcc and the switch SW, and the other terminal of the DC-DC converter section 2 is connected to GND (ground) such as a vehicle body.

  A positive power supply unit 3 and a negative power supply unit 4 are connected to the DC-DC converter unit 2 and each performs a boosting operation. In the present invention, the input of the positive power supply unit 3 is The input voltage of the DC-DC converter 2 is 12V, that is, connected to the power supply voltage of the vehicle. The input of the negative power supply unit 4 is connected to the GND terminal of the DC-DC converter unit 2.

  Further, a load unit 5 such as an LED is connected between the output of the positive power supply unit 3 and the output of the negative power supply unit 4. For example, the positive power supply unit 3 and the negative power supply unit 4 and the vehicle body A positive-side short-circuit detection circuit 3a and a negative-side short-circuit detection circuit 4a for detecting a short circuit or a disconnection are provided. The operation of providing the positive side short circuit detection circuit 3a and the negative side short circuit detection circuit 4a will be described later.

  Then, signals from the positive-side short circuit detection circuit 3a and the negative-side short circuit detection circuit 4a are sent through the protection circuit / control unit 6 to the DC-DC converter unit 2 as appropriate. Therefore, the DC-DC converter 2 includes a converter 21 and a control unit 22 that controls a signal from the protection circuit / control unit 6.

  2 will be described in more detail with reference to FIG. 2. The power supply voltage input from the input terminal Vcc is driven by the control circuit 22 of the DC-DC converter section 2 through the coil L1. Switching is performed by the FET Q1, and the switching boost voltage Vo is generated by this switching.

  Here, the positive power supply unit 3 uses the cathodes of the diodes D1 and D2 as the load unit 5, and the output voltage from the positive power supply unit 3 is (power supply voltage (Vcc) + switching boost voltage (Vo)). .

  On the other hand, the negative power supply unit 4 has the anode side of the diodes D3 and D4 as the load unit 5 side, and the output voltage from the negative power supply unit 4 is connected to the GND potential (GND potential ( 0V) − (switching boosted voltage (Vo)).

  Therefore, the voltage applied to the load unit 5 such as an LED connected between the output of the positive power supply unit 3 and the output of the negative power supply unit 4 is obtained by adding the term of the power supply voltage (Vcc). The voltage (Vcc) + (switching boosted voltage (Vo) × 2) is obtained, and a high voltage is obtained by adding the power supply voltage (Vcc). The number of LEDs that can be lit in series can be increased by an amount corresponding to (Vcc).

  Therefore, in the power supply device of the present invention, the number of lighting of the LEDs can be increased by the amount of the power supply voltage (Vcc) of the vehicle or the like with respect to the load unit 5, so that the cost is not improved so much. Brighter vehicular lamps can be obtained, and the efficiency in terms of cost and material can be improved.

  However, when the DC-DC converter unit 2, the inverter positive power supply unit 3, and the negative power supply unit 4 are used, a portion having a voltage higher than the power supply voltage (Vcc) or a voltage lower than the GND potential is generated. Sometimes it is necessary to be careful not to make contact with the wiring of other parts, that is, the part wired with the power supply voltage (Vcc).

  Therefore, short circuit detection circuits 3a and 4a as shown in FIG. 1 are provided, and if a short circuit with the vehicle body or the like occurs, the protection circuit control unit 6 operates and performs a corresponding operation such as switching off the switch SW, The DC-DC converter 2 and the load unit 5 are protected.

  According to the present invention, for one DC-DC converter unit 2, a positive power source unit 3 connected to the power source voltage (Vcc) and a negative power source unit 4 connected to the GND potential are provided. Since the load unit 5 is connected between the negative power source unit 4 and the negative power source unit 4, two DC booster units, that is, the positive power source unit 3 and the negative power source unit 4 can be driven by one DC-DC converter unit 2. In addition, the cost can be reduced by simplifying the circuit, and the highest voltage obtained by adding the input voltage as well as the positive and negative as the booster circuit by one DC-DC converter unit 2 can be obtained.

  Further, when driven by one DC-DC converter unit 2, the positive power source unit 3 and the negative power source unit 4 are turned on with completely the same synchronization. For example, a plurality of DC-DC converters such as two DC-DC converters Compared with the case where the same LED is lit using the LED, there is no phase shift or the like, and accurate and beautiful lighting can be performed.

  Furthermore, as described above, the fact that only one DC-DC converter 21 is required means that only one control unit 22 for controlling the DC-DC converter 21 is required, and the control unit 22 is controlled and monitored. Therefore, since only one safety circuit or the like is required, the overall configuration can be almost halved, and the overall size can be reduced and simplified.

  In addition, in this embodiment, although demonstrated using the example used as a power supply of vehicle lamps, such as a headlamp, a rear combination lamp, a fog lamp, and DRL, it is not restricted to this, The power supply for LED street lights, the power supply for LED lighting fixtures, etc. It can be used as various power supply devices.

It is a block diagram which shows the structure of the power supply device 1 which concerns on this invention. FIG. 3 is an explanatory diagram showing a main part of the same power supply device 1 in a circuit diagram. It is a schematic circuit diagram which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Power supply device 2 ... DC-DC converter part 21 ... Converter part 22 ... Control part 3 ... Positive power supply part 4 ... Negative power supply part 5 ... Load part 6 ... Protection circuit and control part

Claims (2)

  In the booster circuit that boosts the power supply voltage, the DC-DC converter section has a positive power supply section that performs a boosting operation in the positive potential direction with reference to the input voltage, and a ground side that has this input voltage. A configuration in which a negative power supply unit that performs a boosting operation in the negative potential direction with respect to the ground voltage is connected, and the load is driven with a differential voltage between the output of the positive power supply unit and the output of the negative power supply unit. A power supply device that is boosted.   2. The power supply apparatus according to claim 1, wherein when a protection circuit is provided between the positive power supply unit and the negative power supply unit, the protection circuit is provided in both power supply units.

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