JP2011078272A - Power supply device for in-vehicle equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a power supply device for in-vehicle equipment capable of certainly operating in-vehicle equipment even when a power-supply voltage is lowered largely by starting or the like. <P>SOLUTION: The power supply device for in-vehicle equipment includes a main switch 2 connected to a vehicle power supply 1 loaded on a vehicle, a first constant-voltage circuit 3 supplied with a voltage from the vehicle power supply 1 through the main switch 2, and a second constant-voltage circuit 4 supplied with an output voltage from the first constant-voltage circuit 3. The first constant-voltage circuit 3 is configured for stepping up and down a voltage while the second constant-voltage circuit 4 is configured for stepping down a voltage. The main switch 2, the first constant-voltage circuit 3, and the second constant-voltage circuit 4 are connected in series. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply device for an in-vehicle device that is used as a control power source for an in-vehicle generator motor that operates as a starting motor when an internal combustion engine is started.

  When the on-vehicle generator motor is operated as a starter motor for starting the internal combustion engine, an excessive current flows from a vehicle power source such as a battery, so that the power supply voltage is greatly reduced. When the voltage of the vehicle power supply falls below the minimum operating voltage of the electronic control unit that electronically controls the vehicle, the electronic control unit stops. The on-vehicle generator motor becomes incapable of starting control when the operation of the electronic control device is stopped. For this reason, even when the voltage of the vehicle power supply falls below a predetermined value, a power supply device for in-vehicle devices that normally operates the electronic control device is required.

  By the way, as a power supply device for in-vehicle equipment that causes the battery power supply to suddenly drop when the starter is activated when the engine is started, a step-down chopper power supply circuit and a series power supply are connected in series. Is low, a technique for preventing deterioration of the minimum operating voltage due to a voltage drop in the chopper power supply circuit by turning on a switching element that bypasses the chopper power supply circuit has been proposed (for example, see Patent Document 1).

Japanese Patent No. 2920929

  However, in the technique disclosed in Patent Document 1, when the voltage of the battery power supply is lowered to a predetermined voltage (normally 5 V) output from the series power supply, the constant voltage circuit reduces the predetermined voltage (normally 5 V). It cannot be maintained and the voltage drops according to the battery voltage. For this reason, the electronic control device becomes inoperable because the voltage supplied from the power supply circuit falls below the minimum operating voltage, and the control stops. As described above, in the technique disclosed in Patent Document 1, there is a problem that the on-vehicle generator-motor may not be able to be controlled by stopping the operation of the electronic control device.

  The present invention has been made in order to solve such a problem, and provides a power supply device for an in-vehicle device that can reliably operate the in-vehicle device even when the power supply voltage is drastically lowered at the time of starting or the like. Is.

  A power supply device for an in-vehicle device according to the present invention includes a bridge rectifier circuit connected to an in-vehicle generator / motor and an electronic control device that supplies a control signal for controlling the in-vehicle generator / motor to the bridge rectifier circuit. A power supply device for an in-vehicle device serving as a power source for a device, a main switch connected to a vehicle power supply mounted on a vehicle, and a first constant voltage circuit to which a voltage from the vehicle power supply is supplied via the main switch And a second constant voltage circuit to which an output voltage from the first constant voltage circuit is supplied, and the first constant voltage circuit is configured as a step-up / down circuit, and the second constant voltage circuit is stepped down. The circuit configuration is such that the main switch, the first constant voltage circuit, and the second constant voltage circuit are connected in series.

According to the power supply device for an in-vehicle device according to the present invention, a main switch connected to a vehicle power supply mounted on a vehicle, a first constant voltage circuit to which a voltage from the vehicle power supply is supplied via the main switch, And a second constant voltage circuit to which an output voltage from the first constant voltage circuit is supplied, wherein the first constant voltage circuit is configured as a step-up / step-down circuit, and the second constant voltage circuit is configured as a step-down circuit. Since the main switch, the first constant voltage circuit, and the second constant voltage circuit are connected in series, the in-vehicle device is reliably operated even at a power supply voltage lower than the minimum operating voltage of the in-vehicle device. be able to.

It is a circuit block diagram explaining the power supply device of the vehicle equipment which concerns on Embodiment 1 of this invention. It is a block diagram which shows the connection state of a bridge rectifier circuit and a charge pump circuit. It is a chart figure which shows the state of the output voltage of the 1st constant voltage circuit with respect to a power supply voltage, and the output voltage of a 2nd constant voltage circuit.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a power supply device for an in-vehicle device according to the invention will be described with reference to the accompanying drawings.

Embodiment 1 FIG.
FIG. 1 is a circuit block diagram illustrating a power supply apparatus for an in-vehicle device according to Embodiment 1 of the present invention. In FIG. 1, a power supply device 100 includes a vehicle power source 1 such as a battery, a main switch 2 that cuts off power supply from the vehicle power source 1, and a first constant voltage circuit that is connected in series with a main switch 2 and includes a step-up / down circuit described later. 3. A second constant voltage circuit 4 comprising a step-down circuit that outputs the constant voltage Vs with the output voltage of the first constant voltage circuit 3 as an input is provided.

  The first constant voltage circuit 3 is a step-down control switch 31 that is always turned on during step-up control, a commutation diode 32 for step-down control, a coil 33, a switch 34 for step-up control, a reverse current blocking diode 35, a capacitor 36, The voltage detection circuit 37, the constant voltage control error amplifier 38, and the first voltage control circuit (Vm voltage control circuit) 39 that controls the switch 31 or the switch 34 are configured.

  The second constant voltage circuit 4 includes a voltage control switch 41, a stabilization capacitor 42, a voltage detection circuit 43, a constant voltage control error amplifier 44, and a second voltage control circuit (Vs voltage control) that controls the switch 41. Circuit) 45.

  In FIG. 1, reference sign VB is a power supply symbol indicating the output voltage of the vehicle power supply 1 (hereinafter referred to as power supply voltage), and reference sign Vm is a power supply symbol indicating the output voltage of the first constant voltage circuit 3. Reference sign Vs is a power supply symbol indicating the output voltage of the second constant voltage circuit 4.

  The power supply device 100 further includes a gate element 8 that synthesizes a main switch activation signal 5 and a power holding signal 7 from an electronic control device 6 to be described later, and a main switch drive circuit 9 that controls the drive of the main switch 2 by a signal from the gate element 8. The reference voltage switching means for switching the high-accuracy reference voltage 10 to which the output voltage Vm of the first constant voltage circuit 3 is input and the low-accuracy but high-accuracy reference voltage 11 to which the power supply voltage VB is input. A voltage switching circuit 12 and a reset circuit 13 for controlling the electronic control device 6 are provided.

The electronic control unit 6 supplies a motor control signal to the bridge rectifier circuit 14 formed of a MOS-FET, and the bridge rectifier circuit 14 supplies rectified power to the armature winding 15 of the generator motor. Thereby, the generator motor is driven and controlled. The electronic control device 6 is constituted by a microcomputer and is supplied with the output voltage Vs of the second constant voltage circuit 4.

  A first charge pump circuit 16 and a second charge pump circuit 17 are connected to the MOS-FET of the bridge rectifier circuit 14. The MOS-FET constituting the upper arm is driven based on the first charge pump circuit 16, and the MOS-FET constituting the lower arm is driven based on the second charge pump circuit 17.

  FIG. 2 is a block diagram showing a connection state between the bridge rectifier circuit 14 and the first and second charge pump circuits 16 and 17. In FIG. 2, a bridge rectifier circuit 14 constitutes a pre-driver circuit 141 that drives the bridge upper arm, a MOS-FET 142 that constitutes the bridge upper arm, a pre-driver circuit 143 that drives the bridge lower arm, and a bridge lower arm. A MOS-FET 144 is provided. In FIG. 2, the same reference numerals as those in FIG. 1 denote the same parts.

  The power supply apparatus for the in-vehicle device according to Embodiment 1 is configured as described above, and the operation thereof will be described next with reference to FIG. FIG. 3 is a chart showing the states of the output voltage Vm of the first constant voltage circuit 3 and the output voltage Vs of the second constant voltage circuit 4 with respect to the power supply voltage VB.

  In FIG. 3, the horizontal axis indicates the power supply voltage VB, and the vertical axis indicates the output voltage Vm of the first constant voltage circuit 3 and the output voltage Vs of the second constant voltage circuit 4. The broken line is the state of the output voltage Vm of the first constant voltage circuit 3, and the solid line is the state of the output voltage Vs of the second constant voltage circuit 4.

  As shown in FIG. 3, when the power supply voltage VB is higher than the output voltage Vm of the first constant voltage circuit 3, the output voltage of the first constant voltage circuit 3 is stepped down to Vm and the output of the first constant voltage circuit 3 is output. When the power supply voltage VB is lower than the voltage Vm, the output voltage of the first constant voltage circuit 3 is boosted to Vm.

  The second constant voltage circuit 4 receives the output voltage Vm of the first constant voltage circuit 3 and controls the output voltage to a constant voltage Vs. However, since the output voltage of the first constant voltage circuit 3 is maintained at Vm, The output voltage Vs of the second constant voltage circuit 4 can be output without depending on the input of the power supply voltage VB. Here, as a specific set value, the output voltage Vs of the second constant voltage circuit 4 is generally 5 V, the output voltage Vm of the first constant voltage circuit 3 is optimized for loss, and the second constant voltage circuit 4 The output voltage Vs is set to about 7 V in view of the stable output and the output voltage setting of first and second charge pump circuits 16 and 17 described later.

  In FIG. 3, when the power supply voltage VB is 3 V or less, the output voltage Vm of the first constant voltage circuit 3 and the output voltage Vs of the second constant voltage circuit 4 both stop voltage output. This is a value set by the lower limit voltage at which the vehicle power supply 1 is determined to be in the normal range. The electronic control device 6 in FIG. 1 detects the power supply voltage VB, and from the power holding signal 7 to the gate element 8 and the main switch. By controlling the main switch 2 via the drive circuit 9, power supply to the first constant voltage circuit 3 is cut off, and the output voltage Vm of the first constant voltage circuit 3 and the output voltage Vs of the second constant voltage circuit 4. It is possible to stop.

  Since the main switch 2 can be controlled from the main switch activation signal 5 in addition to the control route from the power holding signal 7, the main switch 2 is turned off from the two routes of the power holding signal 7 and the main switch activation signal 5. The main switch 2 is turned off only when the commands are simultaneously established.

Further, the turn-off command of the main switch 2 is configured so that the output of the first constant voltage circuit 3 in the subsequent stage is also stopped. The first constant voltage circuit 3 takes in a signal from the gate element 8 that is an off command of the main switch 2 and stops the output voltage Vm of the first constant voltage circuit 3 simultaneously with the main switch 2. As a result, even when an ON failure occurs in the main switch 2, it is possible to stop the outputs of the first constant voltage circuit 3 and the second constant voltage circuit 4.

  Next, the operation of the first constant voltage circuit 3 will be described. In FIG. 3, when the power supply voltage VB is higher than the output voltage Vm of the first constant voltage circuit 3, the step-down circuit constituted by the switch 31, the coil 33, the diode 35, the capacitor 36 and the diode 32 causes the first constant voltage The output voltage Vm of the circuit 3 is kept constant. At this time, the switch 34 is off.

  When the power supply voltage VB is lower than the output voltage Vm of the first constant voltage circuit 3, the booster circuit composed of the coil 33, the switch 34, the diode 35, the capacitor 36 and the diode 32 causes the first constant voltage circuit 3 to The output voltage Vm is kept constant. At this time, the switch 31 is on.

  In the step-up / step-down circuit in the first constant voltage circuit 3, the switch 31 and the switch 34 are connected in series via the coil 33. Therefore, when the switch 31 and the switch 34 are simultaneously turned on, an excessive current flows and the switch 31. , 34, or the coil 33 may be burned out, and when the switch 31 and the switch 34 are simultaneously turned on and an excessive current flows, a protection circuit configured to turn off the switch 34 is added. Note that a specific description of the protection circuit is omitted here.

  Next, the operation of the second constant voltage circuit 4 will be described. The second constant voltage circuit 4 is a linear control type step-down circuit that takes the output voltage Vm of the first constant voltage circuit 3 as an input and performs constant voltage control of the output voltage Vs by constant voltage feedback control. High voltage accuracy is often required. Therefore, in order to improve the accuracy of the output voltage Vs of the second constant voltage circuit 4, it is necessary to improve the accuracy of the reference voltage compared by the error amplifier 44.

  Therefore, a reference voltage 10 having the relatively stable output voltage Vm of the first constant voltage circuit 3 as an input, and a reference voltage having a low-accuracy and high-speed output for a wide range of input voltages with the power supply voltage VB as an input. 11 is set as a reference voltage. Then, this is switched by the reference voltage switching circuit 12 and input to the error amplifier 44, so that the output voltage Vs is made highly accurate by the control by the reference voltage 10 in a steady state and the circuit operation immediately after the power is turned on is unstable. During a transient, control is performed by switching to a high-speed reference voltage 11 with low accuracy. Thereby, a stable target voltage of the output voltage Vs can be obtained. The reference voltage output from the reference voltage switching circuit 14 is shared by the error amplification circuit 38 that controls the first constant voltage circuit 3, and can also be shared by the voltage reset circuit 13 and the like, thereby simplifying the circuit. Can be measured.

  Next, operations of the bridge rectifier circuit 14, the first charge pump circuit 16, and the second charge pump circuit 17 will be described with reference to FIG. In the MOS-FET 142 constituting the upper arm and its pre-driver 141, the MOS-FET 144 constituting the lower arm, and the pre-driver 143, the voltage source for driving the MOS-FET 142 constituting the upper arm is The one charge pump circuit 16 supplies the output voltage VO1 to the gate of the MOS-FET 142 via the pre-driver 141 to drive the MOS-FET 142. For driving the MOS-FET 144 constituting the lower arm, the output voltage VO2 of the second charge pump circuit 17 is supplied to the gate of the MS-FET 144 via the pre-driver 143 to drive the MS-FET 144.

The output voltage of the second charge pump circuit 17 and the power supply voltage VB are input to the first charge pump circuit 16, and the output voltage Vm of the first constant voltage circuit 3 is input to the second charge pump circuit 17, respectively. The output voltages of the charge pump circuits 16 and 17 are as follows.
Output voltage VO1 = VO2 + VB = 2Vm + VB of the first charge pump circuit 16
Output voltage VO2 = 2Vm of the second charge pump circuit 17

  Since the upper arm MOS-FET 142 is driven by the output voltage of the first charge pump circuit 16 and the lower arm MOS-FET 144 is driven by the second charge pump circuit 17 as described above, Both the lower arm MOS-FET 144 can be driven with a voltage twice the output voltage Vm of the first constant voltage circuit 3. Accordingly, since the driving voltages of the upper and lower MOS-FETs 142 and 144 can be made uniform without depending on the power supply voltage VB, the switching operation composed of the MOS-FET 142 and the MOS-FET 144 can be balanced and stable. The bridge rectifier circuit 14 can be controlled.

  As described above, according to the power supply apparatus for an in-vehicle device according to the first embodiment, by adopting the step-up / down circuit for the first constant voltage circuit 3, even when the power supply voltage is lower than the minimum operating voltage of the electronic device, The control circuit 6 can be operated reliably.

  Further, in the bridge rectifier circuit 14 composed of the MOS-FETs 142 and 144, the charge pump voltage based on the output voltage Vm of the first constant voltage circuit 3 can be obtained, so that the gate drive of the MOS-FETs 142 and 144 is optimized. The bridge rectifier circuit 14 having excellent controllability can be obtained.

  Furthermore, by switching a plurality of reference voltages, it is possible to obtain a power supply device for an in-vehicle device having high accuracy and excellent transient response.

DESCRIPTION OF SYMBOLS 1 Vehicle power supply 2 Main switch 3 1st constant voltage circuit 4 2nd constant voltage circuit 5 Main switch starting signal 6 Electronic controller 7 Power supply holding signal 8 Gate element 9 Main switch drive circuits 10 and 11 Reference voltage 12 Reference voltage switching circuit 13 Reset circuit 14 bridge rectifier circuit 15 armature winding 16 of generator motor first charge pump circuit 17 second charge pump circuit 31 switch 32 commutation diode 33 coil 34 switch 35 reverse current blocking diode 36 capacitor 37 voltage detection circuit 38 error amplifier 39 First voltage control circuit 41 Switch 42 Capacitor 43 Voltage detection circuit 44 Error amplifier 45 Second voltage control circuit 141, 143 Pre-driver circuit 142, 144 MOS-FET
VB Power supply symbol Vm Power supply symbol indicating the output voltage of the first constant voltage circuit 3 Vs Power supply symbol indicating the output voltage of the second constant voltage circuit 4

Claims (6)

A bridge rectifier circuit connected to the vehicle generator motor;
An electronic control device for supplying a control signal for controlling the in-vehicle generator-motor to the bridge rectifier circuit, and a power device for the in-vehicle device serving as a power source for the in-vehicle device,
The power supply for the above-mentioned in-vehicle device is
A main switch connected to the vehicle power supply installed in the vehicle;
A first constant voltage circuit to which a voltage from the vehicle power supply is supplied via the main switch;
A second constant voltage circuit to which an output voltage from the first constant voltage circuit is supplied;
With
The first constant voltage circuit is configured as a step-up / step-down circuit, the second constant voltage circuit is configured as a step-down circuit, and the main switch, the first constant voltage circuit, and the second constant voltage circuit are connected in series. A power supply device for an in-vehicle device.   The power supply apparatus for an in-vehicle device according to claim 1, wherein the bridge rectifier circuit is configured by a MOS-FET.   The first constant voltage circuit is configured to include a three-part serial connection of a first switch, a coil, and a second switch, and in the input voltage range where the step-up operation and the step-down operation overlap, the first switch The power supply apparatus for an in-vehicle device according to claim 1, wherein the second switches are configured not to be turned on simultaneously.   The power supply device for an in-vehicle device according to any one of claims 1 to 3, wherein a plurality of reference voltages for the first constant voltage circuit and the second constant voltage circuit are set and shared. .   5. The power supply apparatus for an in-vehicle device according to claim 4, further comprising reference voltage switching means for switching the reference voltage according to an input voltage state. Comprising first and second charge pump circuits for outputting different voltages for driving the bridge rectifier circuit;
The first charge pump circuit outputs a voltage obtained by adding the output voltage of the second charge pump circuit to the voltage of the vehicle power supply,
6. The on-vehicle apparatus power supply device according to claim 1, wherein the second charge pump circuit outputs a double value of an output voltage of the first constant voltage circuit. 7.

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