JPS62126370A - Bipolar switching power source - Google Patents

Abstract

PURPOSE:To obtain a bipolar switching power source having good efficiency, by using an auxiliary inductor not only to take-in the charge of one capacitor but also to apply inverse electromotive force to the other capacitor. CONSTITUTION:An auxiliary inductor 13 is changed over by switches 14A, 14B so as to be alternately connected to two capacitor 12A, 12B, which are parallelly connected to DC sources 6A, 6B, in parallel and, by this changeover operation, energy is discharged to the auxiliary inductor 13 from the capacitor ready to gradually increase in voltage and stored in the auxiliary inductor 13. This energy is transferred to the other capacitor in the next changeover timing. By this method, because abnormal energy generated by the inverse electromotive force of the main inductor of a load circuit 11 is discharged through the auxiliary inductor, abnormal voltage is absorbed and a switching power source having good efficiency can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application"
This invention relates to a bipolar switching power supply used as a power supply when looking at voltage applied current characteristics or current applied voltage characteristics of each terminal.

BACKGROUND OF THE INVENTION IC tests can be roughly divided into DC tests, which check the DC characteristics of terminals, and active tests, which check whether a circuit performs a predetermined operation. DC testing consists of a voltage application current measurement mode that tests whether or not a specified current flows when a specified DC voltage is applied to an IC terminal, and a voltage application current measurement mode that tests whether a specified current flows to the terminal when a specified current is applied. There is a current mark 7jO voltage measurement mode for testing whether a predetermined voltage is generated.

In order to perform this DC test, DC voltage sources and current sources are prepared in a number corresponding to the number of terminals of the IC under test. These DC voltage sources and DC current sources are required to have high-speed response characteristics in order to shorten test time. For example, voltage mark), 'D
In the current measurement mode, the applied voltage is changed stepwise at high speed, the current value at each voltage point is read at high speed, and the data is updated. Also in the current applied voltage measurement mode, the current value is changed stepwise at high speed, and the voltage at the terminal at each current value is read at high speed. A command to change the voltage or current in a stepwise manner is output as a digital signal from a controller configured by a computer or the like, and the digital signal is DA-converted and given as a control signal.

As described above, DC power supplies used in IC test equipment are required to have high-speed response.

“Conventional technology 4 FIGS. 4 and 5 show conventional DC power supplies.

The example shown in FIG. 1 shows the case where a DC amplifier is used.

In other words, there is a digital human input signal to DAWN device 1! 1 is detected, and the digital human input signal is converted to DA to cause itching.
The output of the operational amplifier 2 is applied to the bases of two offset-connected transistors 3 and 4. A case is shown in which a voltage corresponding to voltage information given to the DA converter 1 is applied to a load 5 connected between the emitter connection point of the transistors 3 and 4 and a common potential point.

The figure shows the state of the ton pressure jJu mode, and the feedback circuit NF
The voltage is stabilized by this.

Further, the example shown in FIG. 5 shows the case of a switching power supply.

In other words, the DC voltage of the DC source 6 is intermittently applied to the load circuit 11 composed of the inductor 8, the capacitor 9, and the load 5 through the switch element 7, and the on/off ratio of the switch element 7 is controlled by the control circuit 10. 5 shows a configuration in which the voltage applied to the circuit 5 can be stabilized and also changed. Here, the diode D is a diode for constructing a discharge path for discharging the back electromotive force generated in the inductor 8 when the switch element 7 is turned off.

[Problem to be Solved by the Invention] In the case of the circuit structure shown in FIG. 4, when the output voltage of transistors 3 and 4 is zero, the voltage between the collector and emitter of transistor 7 is directly applied with the power supply voltage. , large power must be dissipated in transistors 3 and 4. This has the drawback of poor efficiency. In addition, since transistors 3 and 4 generate a large amount of heat, when many power supplies (approximately 10 transistors) are installed in parallel, heat must be dissipated efficiently, which makes thermal design troublesome and increases costs due to heat dissipation. be.

In the case of the circuit structure of the switching power supply shown in FIG. 5, the loss in the switching element 7 is small because the switching element 7 only takes on and off states. Therefore, it has the advantage of being efficient. However, with this circuit structure, the response is fast when changing the voltage in the direction of increasing it, but when changing the voltage, the electric energy stored in the inductor 8 and capacitor 9 must be naturally released through the load 5. For this reason, there is a problem that the voltage decreases slowly and responsiveness deteriorates.

Furthermore, this switching power supply has the disadvantage that it can only apply a voltage of either positive or negative polarity to the load 5.

For this reason, the circuit structure shown in FIG. 6 can be considered.

In this circuit, positive and negative voltages are alternately applied to the load circuit 11 from positive and negative DC sources 6A and 6B by controlling the on and off of switches 7A and 7B, and the on and off ratios of the switches 7A and 7B are appropriately controlled. The purpose is to apply a DC voltage to the load 5 that can be changed from a positive polarity voltage to a negative polarity voltage depending on the selected voltage, but with this circuit structure, for example, when the switch 7A is turned off, Even if switch 7B is turned on immediately after
, 6B, the back electromotive force generated by the inductor 8 is in the opposite direction, so no current can flow through the circuit passing through the switch 7B. Therefore, this circuit is inoperable.

For this reason, the circuit shown in FIG. 7 can be further considered. The circuit shown in this seventh factor has a capacitor 12A for each DC source 6A, 6B,
12B are connected in parallel, and the counter electromotive force generated in the inductor 8 is made to flow to the capacitors 12A and 12B.

Here, in the circuit shown in FIG. 7, switch 7A.

Consider a state in which 7B is operating on and off at a duty ratio of 50%.

When the switch 7A is turned on, as shown in FIG. 8A, (double 17!L 1) flows. This current 1 flows through the inductor 8, so that electromagnetic energy is stored in the inductor 8.

Next, when the switch 7A is turned off and the switch 7B is turned on, the negative DC source 6B is connected to one end of the inductor 8. In this state, the electromagnetic energy stored in the inductor 8 is converted into electrical energy, and a back electromotive force is generated in the inductor 8. The small back force causes the current I2 flowing in the same direction as the upstream ■1 to i'i! u L/ acts to continue and consumes energy. As a result, the current I2 gradually decreases and reaches zero one by one. When the current I2 reaches zero, a current 3 starts to flow from the capacitor 12B, and this current I3 flows through the inductor 8 in the opposite direction to the current line 2. flows to

That is, the current I2 is a current in the opposite direction to the negative DC source 6B. Therefore, the current I2 cannot flow through the DC source 6B, so the current I2 flows through the capacitor IOB. Den 7
4 I2 flows through capacitor IOB, so that capacitor I0BI is charged with voltage -ΔE as shown in FIG. 8E.

The voltage -△E charged in the capacitor IOB is the current I8
The voltage between the terminals of the capacitor IOB returns to the original DC source 6B in the state immediately before the on/off relationship of the switches 7A and 7B is reversed due to the consumption of current ■3 from the moment when it starts to flow.
The voltage returns to the state of −E2.

When the switch 7B is turned off and the switch 7A is turned on, the positive DC voltage is applied to the load circuit 11 again.
At this time, a back electromotive force is generated in the inductor 8, and the electric current lA"bI
A current ■4 flowing in the same direction as s is applied.

When the current 4 passes through the zero cross point, the cycle is reversed and the current 11 takes over.

Current I4 passes from load 5 through inductor 8 to capacitor I
Flows into OA. As a result, the capacitor IOA is charged with +ΔE as shown in the eighth diagram. +ΔE charged in the capacitor IOA is discharged when the current I starts to flow, and the voltage of the capacitor 12A returns to the original voltage +& of the DC source 6A.

In this manner, when the switches 7A and 7B are operating with a duty of 50, the back electromotive force generated in the inductor 8 is equal to the capacitor IOA.

10B can flow, operation is maintained.

However, when the duty is 50%, no voltage is applied to the load 5, so this cannot be said to be a practical state.

Switch 7A is used to apply voltage to load 5.

The on/off ratio of 7B may be set to a state other than 50%. For example, if the switch 7-A is kept on for a long time, the average value of the current 11 flowing through the load becomes thicker than the current I8 flowing in the opposite direction to the current 1, so that a positive voltage can be applied to the load 5. Conversely, if the time when switch 7A is on is shorter than the time when it is off, the electric MEI
The average value of B becomes larger than the average value of current I, and a negative voltage can be applied to the load 5.

However, in the circuit shown in FIG. 7, switch 7A.

If the on/off ratio of 7B is set to a state other than 50%, the capacitor IOA or IOB will be biased to either side and charged repeatedly, and the charged charge will be further charged without being released, causing damage to the capacitor. An abnormally high voltage is charged. Therefore, if the switches 7A and 7B are made of semiconductor elements such as transistors, the switch charged with an abnormally large voltage will be damaged by the abnormal voltage. The time required for this damage to occur is almost instantaneous.

Figure 9 shows the situation at 7. In FIG. 9, the time T1 during which the switch 7A is on is greater than the time T2 during which the switch 7A is off.
The case where the state is set to 1>T2 is shown.

In this state, only a current 11 flows from the inductor 8 toward the load 5, and a current I2 flows when the energy stored in the inductor 8 is released.

The current I2 is a current flowing through the capacitor IOB when the switch 7B is on, as shown in FIG.

For this reason, every time current I2 flows, -
△E is charged and the capacitor I as shown in the 9th [JE]
The voltage of OB gradually increases in the negative direction.

If the switching speed of the switches 'IA and 7B is, for example, a frequency of several KH2 to several tens of KHz, the rate of increase in the voltage of the capacitor IOB will correspond to the switching speed, and the switch 7B will be damaged almost instantaneously. When the duty is reversed, a voltage is charged to the capacitor IOA. Abnormal voltage occurs in capacitor IOA.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned disadvantages and to provide a bipolar switching power supply that operates normally without charging the capacitor.

[Means for resolving the problem] The present invention includes a load circuit in which a capacitor and a load are connected in parallel between one end of an inductor and a common potential point, and a load circuit in which a capacitor and a load are connected in parallel between one end of an inductor and a common potential point; Negative DC by, and a changeover switch that alternately applies the positive and negative DC source voltages to the load circuit.

Two capacitors connected in parallel to positive and negative DC sources, an auxiliary inductor with one end connected to a common potential point, and a switch that alternately connects this inductor in parallel with a capacitor connected in parallel to the DC source. The switch constitutes a bipolar switching power supply.

According to the configuration according to the invention, the auxiliary inductor is alternately connected in parallel to two capacitors connected in parallel to the DC source. Through this switching operation, energy is released from the capacitor whose voltage is gradually increasing to the auxiliary inductor, and energy is stored in the auxiliary inductor.

The electricity stored in the auxiliary inductor is transferred to two capacitors at the next cutting timing.

The hydraulic capacitor, which receives energy from the auxiliary inductor, releases its electrical energy toward the load circuit.

In this way, according to the present invention, the abnormal energy generated by the back electromotive force of the main inductor of the load circuit is transferred to the auxiliary inductor, and the energy is transferred to the forward current path supplying energy to the load circuit via the auxiliary inductor. can be released.

Therefore, the abnormal voltage generated in the capacitor is absorbed, and the increase in voltage is suppressed. However, since electric energy is used without waste, we can provide efficient switching power supplies, and in particular, we can provide bipolar switching power supplies that can provide positive and negative DC voltages to the load. The advantage is that it can be changed at high speed.

"Example" An embodiment of the present invention is shown in the first □□□. In FIG. 1, 11 indicates a load circuit. This load circuit 11 is composed of a main inductor 8, a capacitor 9 and a load 5 connected in parallel between one end of the main inductor and a common potential point G.

6A, 6B indicate positive and negative DC sources. These positive and negative DC sources 6A and 6B each have one end connected to a common electric current at point G.
The bent end is connected to one end of the main inductor 8 of the load circuit 11 through switches 7A and 7B. Capacitors 12A and 128 are connected in parallel to the positive and negative direct currents JQ6A and 6B, respectively.

13 indicates an auxiliary inductor. This auxiliary inductor 13
connects one end to the common potential point G and connects one end to the switching switch 1.
4A and 14B are alternately connected to the voltage supply points of the positive DC source 6A and the negative DC source 6B. In other words, by switching the changeover switches 14A and 14B, the auxiliary inductor 13
are alternately connected in parallel to capacitors 12A and 12B.

(Operation of auxiliary inductor 13) Here, the operation of the auxiliary inductor 13 will be explained. Switches 14A and 14B are the main switch 7A.

It is driven on and off regardless of the on and off operations of 7B. Here, in order to simplify the explanation, switch 14A,
14B is turned on at a constant cycle with a duty ratio of 50%,
It is assumed that off-loading is carried out.

Assuming that main switches 7A and 7B operate on and off at 50% duty, capacitors 12A and 12B
The charging voltages of are in the same state.

In this state, when the switches 14A and 14B are turned on and off with a duty of 50 channels using the rectangular waves shown in FIG.
I2□+I2B+I24 is a 12A capacitor.

12B and the auxiliary inductor 13.

That is, when the switch 14A is on, a current I21 flows from the DC i6A toward the auxiliary inductor 13. current I
When the switch 14A is turned off while 2+ is flowing through the auxiliary inductor 13, and the switch 14B is turned on in turn, a current 1iI22 flows through the capacitor 13B due to the back electromotive force generated in the auxiliary inductor 13. This current I2
□ flows in the same direction as the current I21, so the capacitor 13
B is charged with a negative voltage -ΔE2□ as shown in FIG. 2E.

When the electric current taI2□ gradually decreases and reaches zero, the current 12. begins to flow. The current r2g is in the 1ψ direction with respect to the current ■2□ that has been flowing so far. As the current I28 flows, the capacitor 12
The voltage -ΔE22 charged to B is gradually returned to zero.

Next, when the switch 14A is turned on again and the switch 14B is turned off again, a current I24 which is the same as the current I28 and gradually decreases flows through the auxiliary inductor 13. This current I2 is 7
The back electromotive force of the 1n auxiliary inductor 13 becomes the source.

Since the current I24 is in the opposite direction to the positive DC i6A, it flows through the capacitor 12A, and +ΔE11 flows through the capacitor 12A.
to charge. When the current I24 reaches zero, the current I2, which is the source current of the capacitor 12AfX, flows into the auxiliary inductor I3. This current 121 is in the opposite direction to current I24.

In this way, each time the changeover switches 12A and 12B are turned on alternately, the energy accumulated in the auxiliary inductor I3 on the positive side is transferred to the capacitor 13B on the negative side as a current I2□, and the energy is accumulated in the auxiliary inductor 13 on the negative side. Energy is electric current■24. It is transferred to capacitor 12B as a capacitor.

Although the explanation so far has been made assuming that the voltages of the capacitors 12A and 12B are equal, the energy transferred from the positive side to the negative side and the energy transferred from the negative side to the positive side are equal and balanced. Therefore, the energy transfer is in a state of zero.

At this point, when the on/off ratios of the earth switches 7A and 7B are removed from the 50% state and a voltage is supplied to the load 5, either one of the capacitors 12A or 12B begins to be charged with voltage.

For example, if the main switch 7A is turned on for a longer time in order to apply a positive voltage to the load 5, the capacitor 12B will be gradually charged with Iπ voltage (110) due to the reason explained earlier, and the voltage will gradually increase in the negative direction. The present east is created by increasing by 1 noro.

In this state, the current flowing through the auxiliary inductor 13 loses its balance, and the current I23 flowing from the capacitor 12B is larger than the current I21 flowing from the capacitor 12A.
Becomes the first man in charge of I21. This situation is shown in FIG. 2F.

When the relationship between currents I211 and I21 becomes I2B>I21, auxiliary inductor 13 receives and takes large energy from capacitor 12B, and transfers that energy to capacitor 12.
Perform the movement to move to A. In other words, the energy transferred by the current I24 is larger than the energy transferred by the current I22, and the energy moves from the negative side to the positive side. The energy transferred to the positive side is released to the load circuit 11 while the switch 7A is turned on.

The electrical energy thus stored in the capacitor 12B due to the back electromotive force of the main inductor 8 is transferred to the positive side capacitor 12A via the auxiliary inductor 13, and is again supplied to the load circuit 11 from the capacitor 12A.

Since a large current I211 flows from the capacitor 12B to the auxiliary inductor 13, no negative voltage is accumulated in the capacitor 12B.

This prevents the capacitor 12B from being charged with a voltage that increases in the negative direction.

When applying a negative polarity voltage to the load 5, the on period of the switch 7A becomes shorter and the on period of the switch 7B becomes longer. In this state, the main inductor 8 is connected to the capacitor 12A.
Charging is performed by the back electromotive force from the capacitor 12A.
The voltage of will gradually rise in the positive direction.

However, the current I21 flowing from the capacitor 12A to the auxiliary inductor 13 increases, and the current I21 flows from the positive side to the auxiliary inductor 13.
The energy transferred to capacitor 12B increases and that energy is transferred to negative side capacitor 12B.

The energy transferred to capacitor 12B is released to load circuit 11 while switch 7B is on.

The energy stored in capacitors 12A and 12B is proportional to the inductance value of main inductor 8. Therefore, it is preferable that the inductance value of the auxiliary inductor 13 provided to carry the energy is selected to be approximately equal to that of the main inductor 8.

In this way, it is possible to obtain a bipolar switching power supply that operates normally even when voltages in both positive and negative directions are applied to the load circuit 11.

"Specific Embodiment" FIG. 3 shows a specific embodiment of the present invention. In other words, the main switches 7A and 7B and the auxiliary switches 14A and 14B
The following is a concrete example of the drive circuit.

16 is a switch drive circuit for driving the main switches 7A and 7B, and 17 is a switch drive circuit for driving the auxiliary switches 14A and 14B.

The switch drive circuit 16 can be composed of, for example, operational amplifiers 18 and 19, a triangular wave generator 21, and a gate drive circuit 22. For example, a voltage Vin proportional to the voltage to be applied to the load 5 is applied from the DA converter l to the non-inverting input terminal of the operational amplifier 18.

The DC voltage applied to the load 5 is applied to the inverting input terminal of the operational amplifier 18 through the feedback circuit NF to balance it with the input voltage Vin. The output of the operational amplifier 18 has Vin-V.
NF is output, and the output voltage Vin-VNF of 7 is applied to the non-inverting input terminal of the operational amplifier 19.

A triangular wave generator 21 is connected to the inverting input terminal of the arithmetic intensifier 19.
gives a triangular wave. The triangular wave and Vin VNF output from the operational amplifier 18 are compared, and the operational amplifier 19
Outputs a square wave to the output. The duty of this rectangular wave changes depending on the input terminal Vin input from the DA converter 1, and a voltage corresponding to the input terminal Vin is applied to the load 5.

The voltage applied to the load 5 is fed back via the feedback circuit NF and compared with the input voltage Vin, so that the voltage of the load 5 is maintained stably.

In this circuit, the output voltage vou' given to the load 5
r is the time the switch 7A is on, 11, and the time the switch 7A is on, t2. DC source 6 A.

When the voltage of 6B is E, is required.

On the other hand, the switch drive circuit 17 on the auxiliary side includes, for example, two pressure comparators 23 and 24, an analog addition circuit 25, an operational amplifier 26, a triangular wave generator 27, and a gate drive circuit 2.
8.

A comparison voltage +Ea is applied to each inverting input terminal of the IE comparators 23 and 24 from comparison voltage sources 29A and 29B. These comparative voltages +Ea and -Eb are DC sources 6A and 6
The voltage of B is selected to be equal to E1 and -E2.

Such a structure [by 42 capacitors 14A and 14B]
When the voltages are equal (2), the outputs of the voltage comparators 23 and 24 are zero, and the operational amplifier 2'6 converts the triangular wave given from the triangular wave generator 27 into a rectangular wave with a duty of 50% and outputs it. do.

Therefore, when the voltages of capacitors 12A and 12B are equal, switches 14A and 14B are driven on and off by a square wave with a duty of 50ch.

When a positive voltage is supplied to the load 5, the capacitor 12B is charged with the voltage for the reason mentioned above. As a result, the voltage comparator 24 outputs a negative voltage proportional to the negative voltage, and provides seven negative voltages to the operational amplifier 26. Therefore, the threshold voltage of the triangular wave changes, and the duty 1 of the rectangular wave output from the arithmetic amplifier 11 hanger 26 changes. In other words, the switch 14B is kept on for a long time.
It operates so that as much of the energy accumulated in the capacitor 13B as possible can be taken into the auxiliary inductor 13.

Next, when a negative voltage is supplied to the load 5, the operational amplifier 2
Conversely, the car-shaped wave output from the capacitor 12A changes to a duty state in which the switch 14A remains on for a long time.
It operates so that a large amount of energy can be taken into the Ichisuke inductor 13 from t.

Input terminal v1o input manually from D A l conversion 7j 1
When the voltage rises, the duty of the rectangular wave output from the switch drive circuit 16 changes transiently, and the pressure 7 applied to the load 5 rapidly increases in the upward or negative direction.

On the other hand, when the voltage applied to the charge 5 is reduced, the on-time of the switch that supplies current to the load circuit 11 is rapidly narrowed down, and in return the on-time of the capacity switch is lengthened. Therefore, the energy stored in the main inductor 8 due to the electricity supplied so far was conventionally consumed through the load, but according to the structure of this invention, the surplus power is transferred to the north switch. through capacitor 12
It is taken into either A or 12B. Therefore, it is given to the load. π pressure can be rapidly reduced.

The switching speed of switches 14A and 14B is the same as that of switches 7A and 7.
It may be independent of the conversion rate of B. Therefore, switch 7A,
The conversion speed may be faster, slower, or the same as that of 7B.

"Operations and Effects of the Invention" As explained above, according to the present invention, the auxiliary inductor 13 and the switches 14A and 14B are provided, The charge accumulated in either one of the capacitors 12A and 12B is taken in as a current by the auxiliary inductor 13.

It is possible to store electromagnetic energy in the auxiliary inductor and transfer the back electromotive force as a current to the northern capacitor.

Due to this energy transfer, the abnormal voltage accumulated in one capacitor due to the back electromotive force of the main inductor 8 disappears, and the switching operation is maintained. As a result, an external switching power supply capable of supplying both positive and negative voltages to the load 5 can be provided.

Furthermore, the back electromotive force generated in the main inductor 8 is consumed by the load 5, and the back electromotive force generated in the main inductor 8 is consumed by the capacitor 12A, not only when the electric current applied to the load 5 is increased in the positive and negative directions, but also when it is changed in the direction of decrease. , 12B, and the voltage decreases faster. Therefore, the voltage applied to the load 5 can be changed at high speed, and when used as a DC source for DC testing of IC test equipment, it generates less heat because it is a switching type, and there is no need to consider heat radiation, reducing the cost of heat radiation. can be reduced.

Furthermore, since it is a switching type, it is highly efficient and can provide a DC testing device with low power consumption.

[Brief explanation of drawings]

FIG. 1 is a connection diagram for explaining one embodiment of the present invention,
FIG. 2 is a waveform diagram for explaining the invention in detail, and FIG.
Figure 1 is a connection diagram for explaining a specific embodiment of the present invention, Figures 1 to 7 are connection diagrams for explaining the conventional ton l+jJ, and Figures 8N and 9 are operation diagrams of the prior art. FIG. 2 is a waveform diagram for explaining. 5: Load, 6A, 6B: DC source, 7A, 7B: Switch, 8: Seven inductors, 9: Capacitor. G: common potential point, 1t: @load circuit, 12A, 12B: capacitor, 13: auxiliary inductor, 14A. 14B: Changeover switch, 16.17: Switch drive circuit. Patent applicant: Atopantest Co., Ltd. Agent
Person Takuho Kusano 1 Decoy I'72 Decoy O 4 Decoy piece 52 O 6 Illustration artist 7 Figure

Claims (1)

[Claims] (1) A: A load circuit with a capacitor and a load connected in parallel between one end of the main inductor and a common potential point, B: A DC source with one end connected to the common potential point, C: A positive and negative current connected to the load circuit. A pair of switches that alternately apply negative DC voltage; D. A pair of capacitors connected in parallel to the positive and negative DC sources to absorb the back electromotive force generated in the main inductor; E. A changeover switch. A bipolar switching power supply consisting of auxiliary inductors alternately connected in parallel to the above pair of capacitors.