JPS62123957A - Ambipolar switching power source - Google Patents

Abstract

PURPOSE:To improve high speed responding property, by providing the load circuit of a condenser and a load arranged in parallel with each other on the one end side of an inductor, with positive and negative DC sources, and by making the counter-electromotive force of the inductor flow to an auxiliary load. CONSTITUTION:An ambipolar switching power source is organized with positive and negative DC sources 6, a switch 7 by a transistor or the like, and a load circuit 11 consisting of an inductor 8, a load 5, and a condenser 9. Then, a voltage detection circuit 12 for detecting the application of a counter- electromotive force generated on the inductor 8 of the load circuit 11, to the DC power sources 6 is set. The detection circuit 12 is organized with a positive and negative comparing voltage source 13 and an arithmetic operation amplifier 14. Besides, with the output of the amplifier 14, a switching element 15 is ON/ OFF-controlled, and an auxiliary load 17 is connected to the positive and negative DC sources 6. Then, the counter-electromotive force generated on the inductor 8 is discharged through the main load 5 and the auxiliary load 17. Besides, by a voltage stabilization circuit 21, voltage applied to the main load 5 is stabilized.

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 voltage application current measurement mode that tests whether 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 when a specified DC voltage is applied to an IC terminal, and a specified voltage is generated at that terminal when a specified current is applied. There is a current applied voltage measurement mode that tests whether or not the current is applied.

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, in the voltage applied 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 data is captured. Also, in the current applied voltage measurement mode, the current value is changed stepwise at high speed.
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" A conventional DC power supply is shown in FIGS. 6 and 7.

The example shown in FIG. 6 shows a case where a DC amplifier is used. In other words, a digital input signal is given to the DA converter 1,
The digital input signal is DA-converted and applied to an operational amplifier 2, and the output of the operational amplifier 2 is applied to two complementary connected transistors 3 and 1. A structure 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 eminter connection point of the transistors 3 and 4 and a common potential point.

The figure shows a voltage application mode, and the voltage is stabilized by the feedback circuit NF.

Further, the example shown in FIG. 7 shows the case of a switching power supply.

The DC voltage from the DC source 6 is intermittently applied by the switch element 7 to the load circuit 11 composed of the inductor 8, the capacitor 9, and the load 5, and the switching ratio of the switch element 7 is controlled by the control circuit 12. A case is shown in which the voltage applied to the load 5 is stabilized and can be changed. Here, the diode 13 is a diode that forms a discharge path for discharging the back electromotive force generated in the inductor 8 when the switch element 7 is off.

"Problem to be Solved by the Invention" In the case of the circuit structure shown in FIG. 6, when the output voltage of transistors 3 and 4 is zero, for example, the voltage between the collector and emitter is the same as the power supply voltage applied. Therefore, a large amount of power must be consumed in transistors 3 and 4. For this reason, some organs are inefficient. Also, since transistors 3 and 4 generate a lot of heat, many power supplies (
If a number of strokes (approximately 10 strokes) are arranged in parallel, heat must be dissipated efficiently, so thermal design is troublesome, and the cost increases due to heat dissipation.

In the case of the circuit structure of the switching power supply shown in FIG. 7, 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 the voltage, but when decreasing the voltage, the electrical energy that is not stored in the inductor 8 and capacitor 9 must be released through the load 5. . For this reason, there is a problem that the voltage decreases slowly and responsiveness deteriorates.

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. 8 can be considered.

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

The purpose of this invention is to be able to output positive and negative voltages while employing a switching power supply system that generates less heat and has high efficiency, and is also capable of changing the voltage at high speed on the positive and negative sides. Furthermore, the present invention aims to provide a bipolar switching power supply that can also supply power to an auxiliary load other than the main load.

[Means for solving the problem] In this invention, positive and negative DC sources are provided for a load circuit in which a capacitor and a load are connected in parallel at one end of an inductor.
In addition to the structure in which the positive and negative DC source voltages are applied alternately by a pair of switches, a voltage detection circuit that detects that a back electromotive force generated in the inductor is applied to the DC source, and this voltage A pair of switching elements are provided, which turn on when the detection circuit detects that a voltage in the opposite direction is applied to the DC source, and connect an auxiliary load in parallel to the DC source to which the voltage in the opposite direction is applied. It is a structure.

According to the structure of the present invention, the back electromotive force generated in the inductor in the switching source is applied in opposite directions to either the positive or negative DC source.

When a back electromotive force is applied to the DC source, the voltage detection circuit detects the state, and the switching element connected to the DC source on the side to which the back electromotive force is applied is turned on to connect the auxiliary load.

As a result, the back electromotive force generated in the inductor is released through the main load and the auxiliary load, forming a back electromotive force release path.

Embodiment FIG. 1 shows an embodiment of a bipolar switching power supply according to the present invention. In Fig. 1, 6A and 6B are positive and negative DC sources,
7A and 7B are switches that can be constructed of transistors, for example, and 11 is a load circuit. Load circuit 1
As explained in FIGS. 6 and 7, 1 includes an inductor 8, and a load 5 and a capacitor 9 connected in parallel to one end of the inductor 8.

In this invention, a voltage detection circuit 12 is provided to detect the application of the back electromotive force generated in the inductor 8 of the load circuit 11 to the two positive and negative DC sources 6A and 6B.

This voltage detection circuit 12 includes positive and negative comparison voltage sources 13A, 1
3B and operational amplifiers 14A and 14B.

In this example, the positive pole of a positive DC source 6A is connected to the inverting input terminal of the operational amplifier 14A, and the calibration voltage source 13 is connected to the non-inverting input terminal 5.
A positive calibration voltage ER1 is given from A.

This positive comparison voltage ER1 is set to have a relationship of E≦ER1 with respect to the voltage E1 of the DC source 6A. Therefore, operational amplifier 1
4A outputs H logic in a steady state.

On the other hand, the negative pole of the negative DC source 6B is connected to the non-inverting input terminal of the operational amplifier 14B, and the negative voltage source 1 is connected to the inverting input terminal.
3B gives a negative comparison voltage -ER2. -E2 and -E
The relationship of R2 is set to 1-E21≦1-EH11.

Therefore, operational amplifier 1.IB outputs H logic in a steady state.

The outputs of operational amplifiers 14A and 1.IB are applied to switch elements 15A and 15B, respectively, and switch elements 15A and 15
Control B on/off. In this example, the switch elements 15A and 15B are PNP type transformers.

The emitter of the transistor constituting the nine-toe switch element 15A is connected to the positive electrode side of the DC source 6A, and the auxiliary load 17A is connected between the collector and the common potential point 16.

The collector of the transistor constituting the switch element 15B is connected to the negative electrode of the negative DC source 6B, and the auxiliary load 17B is connected between the emitter and the common potential point 16.

Auxiliary loads 17A and 17B are auxiliary power supply 18A in steady state.
, 18B to maintain the operating state.

DC sources 6A and 6B are connected with capacitors 19A and 1, respectively.
Connect 9B in parallel.

Here, the voltage detection circuit 12 and the switch element 15A.

The operation of 15B will be explained.

For example, when the switch 7A is turned on, a positive voltage E1 is applied to the load circuit 11. A current 11 flows through the load circuit 11 due to the application of the positive voltage E1. The current 11 flows through the inductor 8 and the main load 5, and the DC source 6A returns through the common potential point 16.

Next, when switch 7A is turned off and switch 7B is turned on, a negative voltage -
E2 is applied, but a back electromotive force is generated in the inductor 8, and this back electromotive force tries to keep the electric current 2 flowing in the same direction as the current I8. For this reason, the electrician 2 attempts to turn off the DC source 6B through the switch 7B.

However, the current I2 cannot flow through the DC source 6B because it acts in the opposite direction to the DC source 6B. Therefore, the current (2) flows through the capacitor 19B and charges the capacitor 19B with an excess voltage ΔE. As a result, the capacitor 19B is charged by adding the surplus voltage -ΔE to the voltage -E2 of the negative DC source 6B, and provides the DC source 6B with an surplus voltage -ΔE of the opposite polarity.

When the capacitor 19B begins to be charged with the surplus voltage -ΔE, the state of the output of the operational amplifier 14B constituting the voltage detection circuit 12 is inverted to the L logic state, and this L logic signal is applied to the switch element 158. The switch element 15B is turned on by the L logic signal, and the auxiliary load 1 is switched on from the common potential point 16.
Flow current ■2 through 7B. As a result, even when the DC source 6B is connected to the load circuit 11, the current 2 can be continued to be supplied to the main load 5. However, for this purpose, the time T during which the electric current is flowing is compared with the time T2 during which the current 2 is flowing, and it is assumed that TI>T2. current I,
, I2 and the voltage changes of the capacitor 19B are shown in FIG.

Next, the case of TI<T2 will be explained. Switch 7B
When is turned on and a negative voltage -E2 is applied to the load circuit 11, a current I3 in the opposite direction to the current 1 flows through the negative circuit 11. Current 3 is supplied from the DC source 6B through the switch 7B.

Next, when the switch 7B is turned off and the switch 7A is turned on, a positive polarity voltage C4 is applied to the load circuit 11.

At this time, the back electromotive force generated in the inductor 8 is generated in the direction of continuing to flow the current I3, and tries to cause the current I4 to flow. Current I4 flows through capacitor 19A;
is charged with an excess voltage of +ΔE. When the capacitor 19A starts to be charged with surplus voltage, the operational amplifier 14A forming the voltage detection circuit 12 outputs L logic, and the switch element 1
Control 5A on. As a result, the current I4 flows to the auxiliary load 17A through the switch element 15A and the common potential point 16.
It returns to the inductor 8 via the main load 5. Current■
Figure 3 shows how the voltages of capacitors 3 and 4 and capacitor 19A change.

In order for the auxiliary loads 17A and 17B to operate as above and form a discharge path for the back electromotive force generated in the inductor 8, even if the switches 7A and 7B are turned on and off alternately, the back electromotive force will not be released from the switches 7A and 7B. It is released within one cycle of the on/off operation. Therefore, the switch 7A can be operated without any inconvenience.

By appropriately changing the on/off ratio of 7B, it is possible to provide the main load 5 with a DC voltage of any value varying from a positive voltage to a negative voltage.

Further, the auxiliary loads 17A and 17B are the auxiliary power source 18A.

Although it operates by receiving power from 18B, by forming a back electromotive force release path for the inductor 8 by the auxiliary loads 17A and 17B, the auxiliary load +7A,
The back electromotive force generated in the inductor 8 can be supplied to 17B. Therefore, the consumption of the auxiliary power supplies 18A and 18B can be reduced, and a power supply with a small capacity can be used.

21 indicates a circuit that stabilizes the voltage applied to the main load 5. That is, the voltage applied to the main load 5 is taken out by the feedback circuit NF, the voltage taken out through the feedback circuit NF is divided by the resistors 22 and 23, and the divided voltage ENF is applied to the inverting input terminal of the operational amplifier 24.

A command voltage vin is applied from the DA converter 1 to the non-inverting terminal of the operational amplifier 24 .

A differential voltage V1n-vNF between the command voltage ■1n and the divided voltage VNF is output from the operational amplifier 24, and this differential voltage vin-
VNF is applied to one input terminal of the voltage comparator 25.

For example, a triangular wave S is applied from a triangular wave generator 26 to the other input terminal of the voltage comparator 25. The DC component of the triangular wave S is the fourth
Assuming that it is 0 as shown in Figure A, the differential voltage vi
If n-VNF=o, the signal output from the voltage comparator 25 becomes a rectangular wave P□ with a duty ratio of 50, as shown in FIG. 4B.

When the differential voltage Vin VNF changes to +E1, the output signal of the voltage comparator 25 becomes a rectangular wave P in which the H logic state has a long period, as shown in FIG. 4C.

Further, when the differential voltage V-VNF changes by -E2Vc, the output signal of the voltage comparator 25 becomes a rectangular wave P3 in which the L logic state shown in FIG. 4 DK has a long cycle.

These rectangular wave signals P□, P2, or P3 are given to the drive circuit 27, and the output of the drive circuit 27 is Pl.

Output each in-phase signal of P2 or P3 and a reverse-phase signal,
This in-phase signal and anti-phase signal are transferred to switch 7A.

7B to alternately apply positive polarity and negative +i voltages to the load circuit 11. When the on/off duty ratio of the switches 7A and 7B is 50, the positive and negative DC voltages applied to the load circuit 11 are at the same time, so the positive and negative voltages cancel each other out, and the load 5 receives no voltage at all. No voltage applied. On the other hand, if the switch 7A is given a rectangular wave P2 with a long H logic time, and the switch 7B is given a rectangular wave P2 with a long L logic time, the load circuit 11 will have a positive voltage for a longer time than a negative voltage. Given. Therefore, a positive voltage is applied to the load 5. On the other hand, switch 7fl? :L
When a rectangular wave with a long logic time is applied and a rectangular wave with a long H logic is applied to the switch 7A, the recoil source 6 is applied to the load circuit 11.
Since a negative voltage is applied from B for a longer time than a positive voltage, a negative voltage is applied to the load 5 on average. Voltage V applied to load 5. UT is the resistance value of resistors 22 and 23 as Rf,
It is obtained when it is Rs.

In this way, feedback is applied so that the voltage applied to the load 5 becomes a constant voltage. Note that in the measurement of applied current and voltage, a current detection resistor (not particularly shown) may be connected in series with the load 5, and a voltage signal generated across the resistor may be fed back to the operational amplifier 24.

"Modified Embodiment of the Invention" FIG. 5 shows a modified embodiment of the invention. In this example, the positive and negative back electromotive forces generated in the inductor 8 are applied to the DC-DC converters 28 and 29, and the DC-DC converters 128,
! A case is shown in which the surplus voltage charged in the co/7J sensors 19A and 19B at =21C is converted into a desired DC voltage and applied to the common auxiliary load 17.

Capacitors 17A and 1 are connected by the tab stain pressure detection circuit 12.
7B detects that a surplus voltage +ΔE or -ΔE has occurred, activates the DC-DC converter 28 or 29 connected to the side where the surplus voltage is generated, converts the surplus voltage to a desired DC voltage, and supplies it to the auxiliary load 17. Replenish power.

Therefore, the auxiliary load J7 is operated by the power of the auxiliary power supply 18 in a steady state, but the DC-DCC converter 28
The power consumption of the auxiliary power source 18 can be reduced by replenishing power from the auxiliary power source 18 and the auxiliary power source 29. Furthermore, diode D
D, D2, and D3 are diodes for blocking backflow.

Since the other effects are the same as those of the embodiment shown in FIG. 1, a redundant explanation thereof will be omitted.

"Operations and Effects of the Invention" As explained above, according to the present invention, the electromagnetic energy stored in the inductor 6 and 8 can be caused to flow through the auxiliary load 17Al17B.

Therefore, any voltage of positive or negative polarity can be applied to the load circuit 11 by selecting appropriate on/off ratios of the switches 7A and 7B.

In addition, especially when increasing the absolute value of the voltage, or decreasing the voltage from the original, the back electromotive force of the inductor is added to the auxiliary load + 7
The response can be made faster since the light is emitted through A and 17B. .

Furthermore, since the back electromotive force generated in the inductor 8 is consumed by the auxiliary load, the capacity of the auxiliary power supply that operates the auxiliary load can be reduced, and in this respect, cost reduction can be expected.

Additionally, since it is a switching type, it is highly efficient and can provide a power source that generates little heat.

[Brief explanation of drawings]

Figure 1 is a connection diagram showing an embodiment of the present invention, Figures 2 and 3 are waveform diagrams for explaining the operation of Figure 1, and Figure 4 is for explaining the operation of the voltage stabilizing circuit. waveform diagram, 5th
The figure is a connection diagram for explaining a modified embodiment of the present invention, and FIGS. 6 to 8 are connection diagrams for explaining a conventional technique. 5: Main load, 6A, 6B: DC source, 7A, 7B: Switch, 8: Inductor, 9: Capacitor, II: Load circuit, 12: Voltage detection circuit, 13A. 13B=comparison voltage source, 14A, 14B: operational amplifier, 1
5A, 15B: Switch element, 16: Common potential point, 17
A, 17B: Auxiliary load, 18A. 18B: Auxiliary power supply, 21: Voltage stabilization circuit, 27: Drive circuit.

Claims (1)

[Claims] (1) A: a load circuit in which a capacitor and a load are connected in parallel to one end of an inductor; B: a positive and negative DC source and a pair of switches that alternately apply positive and negative DC voltages to this load circuit; C. A pair of capacitors connected in parallel to the positive and negative DC sources to absorb the back electromotive force generated in the inductor; D. The back electromotive force generated in the inductor is applied to the pair of capacitors; a voltage detection circuit that detects that the capacitor is charged with a voltage higher than the voltage of the DC source; E, a switch element that connects an auxiliary load in parallel with the DC source using the detection output of the voltage detection circuit; Consists of bipolar switching power supply.