JP3163680B2 - Power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for an electronic device, and more particularly to an increase in current consumption of a load, such as a personal computer and a workstation such as an electronic device having a configuration in which an option board and the like can be added. The present invention relates to a power supply device suitable for a power supply of a device in which is predicted.

[0002]

2. Description of the Related Art Generally, in a personal computer or a workstation or the like, for example, an extension memory board, various interface boards, an option board such as a sound source board, and an expansion slot for additionally expanding peripheral devices such as a hard disk drive are provided. It has a configuration. A part of such peripheral devices and most of the option boards are supplied with power from a power source of a device body such as a personal computer or a workstation.

In such an electronic device, when the number of additional option boards and peripheral devices (hereinafter referred to as "extension boards") increases and the current consumption increases, the power supply from the device main unit becomes large. Supply may be insufficient. In such a case, the power supply to the equipment body becomes insufficient and the equipment body cannot operate normally, or the power supply to the extension board etc. becomes insufficient and the extension board etc. can operate normally. Disappears. Therefore, when there is a possibility of such a situation, it is necessary to provide a dedicated power supply to an extension board or the like separately from the power supply of the device main body.

[0004]

However, if all the power supplies for the extension boards and the like are supplied by separate power supplies, the power supply capability of the power supply of the apparatus body becomes useless. Further, in this case, since the voltage of the power supply of the device main body and the voltage of another power supply hardly coincide completely, the inconsistency of the power supply voltage may cause a malfunction.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is capable of effectively using the output of a power supply of a device main body to supply more power than the output of the power supply to an extension board or the like. Further, it is an object of the present invention to provide a power supply device that does not cause a malfunction of the device body and the extension board.

[0006]

A power supply unit according to the present invention comprises a main power supply means comprising a voltage source whose output is directly connected to a load, and a load current detection means for detecting a magnitude of a load current of the main power supply means. And the switching element is pulsed according to the magnitude of the load current detected by the load current detecting means.
ON / OFF control by width modulation and output current to coil
And an auxiliary power supply for supplying a current to a load by adding an output current of the switching element to an output of the main power supply through the coil, the output of the main power supply being provided. Is supplemented by current addition from the auxiliary power supply means. The auxiliary power supply means preferably comprises a series type chopper means connected between the output terminals of the main power supply means. In this case, the series-type chopper means can be configured to include, for example, an auxiliary power supply serving as an operation power supply, and one end of the auxiliary power supply is connected to a current output terminal side of the series-type chopper means. .

[0007]

In the power supply device of the present invention, only the power shortage is added from the auxiliary power supply to the output of the main power supply and supplied to an extension board or the like without wasting the power supply of the device body, that is, the output of the main power supply. Therefore, the power supply voltage supplied to the extension board or the like completely matches the original main power supply voltage, and there is no possibility of malfunction of the device body and the extension board. That is, in the power supply device of the present invention, the current capacity is increased by detecting the current supplied from the main power supply to the load, and adding the shortage from the auxiliary power supply.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a power supply device according to a first embodiment of the present invention. In FIG. 1, an auxiliary power supply unit 3 is provided between a device body 1 such as a personal computer and a load 2 such as an extension board. The power supply of the device main body 1, that is, the output of the main power supply 11 is connected to the load 2. The main power supply 11 is, for example, a 5V stabilized power supply. A connection line from the main power supply 11 to the load 2, that is, one of power supply lines;
For example, the positive power supply line P is provided with a current detector 12 such as a current transformer (current transformer) that outputs a signal corresponding to a current value flowing through the power supply line P.
The output 2 is appropriately amplified by the amplifier 13 and output as a voltage corresponding to the detected current value. The output of the amplifier 13 is
The signal is applied to a PWM control circuit 14 which performs PWM (pulse width modulation) using the signal as a modulation wave. PWM control circuit 14
Outputs a PWM signal having a predetermined repetition frequency (carrier frequency) and a pulse train whose pulse width changes according to the output of the amplifier 13. This PWM signal is provided to the base of the switching transistor 15. The emitter of the switching transistor 15 is, for example, 10 V
Is connected to the positive side of the auxiliary power supply 16, and the negative side of the auxiliary power supply 16 is connected to the power supply line N on the negative side. The collector of the switching transistor 15 is connected to the positive power supply line P via the coil 17. The collector of the switching transistor 15 is also connected to the negative power supply line N via the diode 18. The cathode of the diode 18 is connected to the collector of the switching transistor 15, and the anode is connected to the negative power supply line N.

Next, the operation of the power supply device configured as described above will be described. The switching transistor 15, the auxiliary power supply 16, and the coil 17 are configured as a series type chopper in which the output of the auxiliary power supply 16 is turned on / off by the switching transistor 15.
5 is turned on / off by the output of the PWM control circuit 14. The PWM control circuit 14 drives the switching transistor 15 with a pulse whose pulse width, that is, the duty ratio changes, according to the detected current value obtained from the current detector 12 via the amplifier 13.

The supply current from the main power supply 11 to the load 2 is represented by I
_1, when the current supplied from the auxiliary power supply 16 to the load 2 and I _2, the current detected by the current detector 12 is I _1. As shown in FIG. 2, the output current I ₁ of the main power supply 11 is a predetermined value,
For example, when trying to exceed a certain allowable current I _R of the device main body 1, the shortage is supplemented by the supply current I ₂ from the auxiliary power supply 16, and an increase in the output current I ₁ of the main power supply 11 is suppressed.
In this case, the switching characteristics of the output pulse width and the pulse repetition frequency of the PWM control circuit 14 that operates according to the current value detected by the current detector 12 are changed by the switching operation of the switching transistor 15 so that the switching transistor 15 The series type chopper including the power supply 16 and the coil 17 is adjusted so as to output the appropriate current value described above. A sufficient current I _L (= I ₁ + I ₂ ) is supplied to the load 2 by adding the supply current I ₂ from the auxiliary power supply 16 to the output current I ₁ of the main power supply 11.

The output of the main power supply 11 of the equipment body 1 is
The output current I ₂ from the auxiliary power supply 16 is added to the supply current I ₁ from the main power supply 11 to the load 2, so that the voltage supplied to the load 2 is 11 is determined. According to the power supply device described above, the main power supply 1
Since only the shortage of the output 1 is added and supplied from the separately provided auxiliary power supply, the main power supply 11 of the device body 1 can be used effectively. Since the power supply voltage supplied to the load 2 becomes completely the same as the supply voltage from the main power supply 11 of the device main body 1, the operation is stabilized and no malfunction occurs.

The above-mentioned circuit of the auxiliary power supply unit 3 only needs to be added to the power supply line from the main power supply 11 of the apparatus main body 1 to the load 2. There is no need to disconnect the power supply line to the load 2. Therefore, the circuit of the auxiliary power supply unit 3 can be added to the device main body 1 as an additional power supply unit, or can be mounted on an additional board or the like. The main power supply 1 of the device body 1
Even if there are a plurality of types of power supply voltages, such as 5 V and 8 V, the circuit of the auxiliary power supply unit 3 does not have a voltage value in the output itself from the auxiliary power supply 16 and adds the current to the main power supply 11. , It is possible to handle a plurality of power supply voltages with one type of circuit.

The above-described circuit shown in FIG. 1 uses a series-type chopper circuit for the auxiliary power supply section 3, so that if the voltage of the auxiliary power supply 16 is 10V, it can be used only for a main power supply voltage of 10V or less. However, in order to make it correspond to the main power supply voltage exceeding the power supply voltage of the auxiliary power supply, the following may be performed. FIG. 3 shows a configuration of a power supply device according to a second embodiment of the present invention. In FIG. 3, FIG.
The same parts as those described above are denoted by the same reference numerals, and detailed description thereof will be omitted. An auxiliary power supply unit 4 is provided between the device body 1 and the load 2. A current detector 12 is provided on one of the power lines from the main power supply 11 to the load 2, for example, the power line P on the positive side, and the output of the current detector 12 is appropriately amplified by an amplifier 13. The output of the amplifier 13 is the PWM control circuit 1
Given to 4. PWM output from the PWM control circuit 14
The M signal is provided to the base of the switching transistor 15. The emitter of the switching transistor 15 is connected to the positive side of the auxiliary power supply 21 of, for example, 10 V, and the negative side of the auxiliary power supply 21 is connected to the power supply line P on the positive side.
The collector of the switching transistor 15 is the coil 1
7 is connected to the power supply line P on the positive side. The collector of the switching transistor 15 is connected to a negative power supply line N via a diode 18 having the polarity shown.

The series type chopper comprising the switching transistor 15, the auxiliary power supply 21 and the coil 17
The output of the auxiliary power supply 21 is turned on / off by the switching transistor 15 to obtain a predetermined output. PWM control circuit 14
Drives the switching transistor 15 with a pulse whose pulse width, that is, the duty ratio, changes according to the detected current value obtained from the current detector 12 via the amplifier 13. In this case, since the output of the auxiliary power supply unit 4 does not limit the output voltage of the main power supply 11 by the output voltage of the auxiliary power supply 21, the current addition is performed even when the output voltage of the main power supply 11 is higher than the output voltage of the auxiliary power supply 21. It can be performed.

[0015]

As described above, according to the present invention,
The power output of the equipment main unit is enabled by adding current from the auxiliary power supply to the output of the main power supply and supplying it to the extension board, etc., without wasting the output of the main power supply of the equipment body. And a power supply device capable of supplying more power than the output of the power supply to the extension board or the like, and having no risk of malfunction of the device body and the extension board.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram showing a configuration of a power supply device according to a first embodiment of the present invention.

FIG. 2 is a current characteristic diagram for explaining the operation of the embodiment of FIG.

FIG. 3 is a circuit configuration diagram showing a configuration of a power supply device according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Device main body, 2 ... Load, 3, 4 ... Auxiliary power supply part, 11 ...
Main power supply, 12 current detector, 13 amplifier, 14 PW
M control circuit, 15 ... switching transistor, 16,
21: auxiliary power supply, 17: coil, 18: diode

Claims (3)

(57) [Claims] 1. A main power supply means comprising a voltage source whose output is directly connected to a load, a load current detection means for detecting a magnitude of a load current of the main power supply means, and a load detected by the load current detection means. Switching element is turned on by pulse width modulation according to the magnitude of current
Off control the output current of the switching element becomes the output current from the collector <br/> current sources for outputting via the coil the co
And an auxiliary power supply for supplying a current to a load by adding the current to the output of the main power supply through a file. The shortage of the output of the main power supply is supplemented by current addition from the auxiliary power supply. And power supply. 2. The auxiliary power supply means comprises a series type chopper means connected between output terminals of the main power supply means.
The power supply as described. 3. The series-type chopper means includes an auxiliary power supply serving as an operation power supply, and one end of the auxiliary power supply is connected to a current output terminal side of the series-type chopper means. Item 3. The power supply device according to Item 2.