JPS62118766A - Bipolar switching power source - Google Patents

Abstract

PURPOSE:To output the positive and negative voltages efficiently by providing a bridge type witch circuit to give the voltage of DC power source alternately in the reverse direction to the load circuit between which the capacitor and the load are connected in parallel on a terminal side of the inductor. CONSTITUTION:By a bridge type switch circuit 13 the voltage of a DC power source 6 is given to a load circuit 11 alternately and in the reverse direction. here, the voltage at the one polarity is given to the load circuit 11. In case in the next timing the voltage at the other polarity is given to the circuit 11, the counter-electromotive force generated at an inductor 8 is discharged through a condenser 14 connected in parallel with the DC power source 6 and supplied to the load 5. The electric charge to the capacitor 14 is discharged to the load circuit 11 when in the next timing the switch circuit 13 goes back to the orignal. By changing the switching-on and -off ratio of the switch circuit 13, the positive DC voltage or negative DC voltage can be given to the load 5.

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 the voltage applied current characteristics or current applied voltage characteristics of each terminal.

``Background of the Invention'' iC tests can be broadly divided into DC tests that check the DC characteristics of terminals and active tests that 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, a number of DC voltage sources and current sources corresponding to the number of terminals of the IC under test are prepared. 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, and the voltage at the terminal at each current value is read at high speed. A command to change the voltage or current stepwise is output as a digital signal from a controller configured by a computer or the like, and the digital signal is converted from digital to analog 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" FIGS. 5 and 6 show conventional DC power supplies.

The example shown in FIG. 5 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 the bases of two complementary-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 a voltage application mode, and the voltage is stabilized by the feedback circuit NF.

Further, the example shown in FIG. 6 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 12. 5 shows a configuration in which the voltage applied to the circuit 5 can be stabilized and also changed. Here, the diode 13 is a diode for forming 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. 5, 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, and Large amounts of power must be dissipated in transistors 3 and 4. This has the disadvantage of poor efficiency. Also, since transistors 3 and 40 generate a lot of heat, many power supplies (
When 10 (about 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. 6, since the switching element 7 only takes on and off states, the loss in the switching element 7 is small (0), which has the advantage of high efficiency. 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 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.

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, a circuit structure shown in FIG. 7 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 7N 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 use a switching power supply system that generates less heat and is highly efficient, while also being able to output positive and negative voltages, and to also be able to change the voltage to the positive and negative sides at high speed. The aim is to provide a flexible switching power supply.

"Means for Solving the Problems" In the present invention, a bridge type switch circuit is provided at one end of an inductor to alternately apply the voltage of a DC power supply in opposite directions to a load circuit in which a capacitor and a load are connected in parallel.

Along with this, a capacitor is connected in parallel with the DC power supply.

According to the configuration of the present invention, the DC power supply is alternately connected to the negative circuit in opposite directions by the bridge type switch circuit.

If a voltage of one polarity is applied to the load circuit, and then a voltage of the other polarity is applied to the load circuit at the next timing, the back electromotive force generated in the inductor will be discharged through the capacitor connected in parallel to the DC power supply. , supplied to the load.

The capacitor is charged with a charge corresponding to the back electromotive force generated in the inductor in response to the voltage washing of the DC power supply, and is charged to a voltage higher than the voltage of the DC power supply.

The charge stored in the capacitor is discharged to the load circuit at the next timing when the switch circuit returns to its original state. After the charging voltage of the capacitor returns to a state equal to the voltage of the DC power supply, current is supplied from the DC power supply to the load circuit.

In this way, the back electromotive force generated in the inductor when the voltage of one polarity is applied to the load circuit and then switched to the other polarity can be discharged through the capacitor connected in parallel to the DC power supply. As a result, by changing the on/off ratio of the switch in the bridge type switch circuit, a positive DC voltage and a negative DC voltage can be applied to the load.

"Embodiment" FIG. 1 shows an embodiment of the present invention. In Figure 1, 1
1 indicates a load circuit. This load circuit is composed of an inductor 8, a capacitor 9, and a load 5, as in the case of the switching power supply shown in FIG.

In the present invention, the DC voltage of the DC power source 6 is supplied to the load circuit 11 with the polarity alternately reversed by the switch circuit 13, and a capacitor 14 is connected to the DC power source 6 in parallel.

The switch circuit 13 bridge-connects four switch elements 7A, 7B, 7C, and 7D each consisting of, for example, a transistor, connects the positive terminal of the DC power supply 6 to the connection point A between the switch elements 7A and 70, and connects the switch elements 7B and 7D. The negative terminal of the DC power supply 6 is connected to the connection point B of the .

In this example, the connection point C between the switch elements 7A and 7B is connected to a common potential point, and the connection point C is connected to one end of each of the capacitor 9 and the load 5 of the load circuit 11.

A connection point between switch elements 7C and 7D is connected to an input terminal of load circuit 11, that is, one end of inductor 8.

Switch elements 7A and 7D and 7C and 7B are each driven by switch signals of the same polarity.

In this example, the drive circuit 15 drives the switch elements 7A and 7.
A case is shown in which the switching elements 7C and 7B are controlled to be switched in the same phase, and the switching elements 7A and 7D are controlled to be switched in the opposite phase.

Here, the operation of the switch circuit 13 and the capacitor 14 will be explained in advance. For example, when switch elements 7C and 7B are turned on, a positive voltage is applied to load circuit 11 from power supply 6. Due to this positive voltage, a current 11 increasing in the positive direction flows as shown in FIG. 2A, and electromagnetic energy is stored in the inductor 8 in proportion to the time the electric current 1 flows.

Now switches 7C and 7B are turned off, and switch 7A
, 7D are turned on, a negative voltage is applied to the load circuit 11. In other words, the positive side of the power supply 6 is connected to the common potential point side of the load circuit 11, and the negative side of the power supply 6 is connected to the load circuit 1.
It is in a state where it is connected to one end side of the first inductor 8.

By switching the switch, the current I flowing through the inductor 8 and the load 5 changes to a current I2K which follows a decreasing trend. The current 2 continues to flow in the same direction as the current 1 in the load circuit 11 due to the back electromotive force of the inductor 8, but it flows in the opposite direction to the DC power source 6. However, since the electric current 2 cannot flow in the opposite direction to the DC power supply 6, it flows through the capacitor 14. Current I in capacitor 14
2 flows, the capacitor 14 is charged with a surplus voltage +ΔE in addition to the voltage E of the DC power supply 6. The voltage change across capacitor 14 is shown in FIG. 2B.

Switch elements 7A and 7D are turned off and 70.7
When B is switched on, a positive voltage is applied from the DC power supply 6 to the load circuit 11 again. As a result, a current Il increasing in the positive direction flows through the load circuit 11 and stores electromagnetic energy in the inductor 8. Immediately after switch elements 7A and 7D are turned off and switches 7C and 7B are turned on, excess voltage +ΔE charged in capacitor 14 is released to load circuit 11. After the surplus voltage +ΔE becomes zero, the current ■l flowing through the load circuit 11 is supplied from the DC source 6.

In this way, the load circuit 11 receives the current 11 supplied from the DC source 6 and the back electromotive force of the inductor 8, which is transferred to the capacitor 14.
For example, if the time when current 1 is flowing is Tl, and the time when current 2 is flowing is T2, then if TI>T2, a positive polarity voltage is applied to load 5. is given.

On the other hand, when the duty ratio is reversed and becomes T1 < T2, the time T2 during which the switch elements 7A and 7D are on is longer than the time T1 during which the switch elements 7C and 7B are on.
becomes longer. Therefore, when the switch elements 7A and 7D are turned on, the current flow 3 flows through the load circuit 11 in the opposite direction to the current flow 1, as shown in FIG. 3A. The current 3 flowing through the switch elements 7A and 7D does not flow into the capacitor 14 because it is in the forward direction with respect to the DC power supply 6.

In this state, switch elements 7A and 7D are turned off, and 7C,
When 7B is turned on, the positive electrode of the DC power source 6 is connected to the connection point, and the connection point C is connected to the negative electrode of the DC source 6. As a result, the current supply voltage 4 is supplied by the back electromotive force of the inductor 8.
is switch element 7C.

7B to the capacitor 14. Therefore, in this case, the capacitor 14 is charged with an excess voltage +ΔE when viewed with reference to point CB8. This surplus voltage element ΔE is discharged toward the load 5 when the switching elements 7A and 7D are turned on.

In this way, according to the invention, the switching elements 7A, 7
Positive and negative voltages can be applied to the load 5 by appropriately selecting the duty ratios of L), 7C, and 7B.

Reference numeral 16 indicates a circuit that stabilizes the voltage applied to the load 5. In other words, the voltage applied to the load 5 is taken out by the feedback circuit NF, the voltage taken out through the feedback circuit NF is divided by the resistors 17 and 18, and the divided voltage EI
'Ji:: is applied to the inverting input terminal of the operational amplifier 190.

A command voltage Vin is applied from the DA converter 1 to the non-inverting input terminal of the operational amplifier 19.

Command voltage V in and divided voltage VN from operational amplifier 19
FQ difference voltage Vin -VNF is output, and this difference voltage V
in-VNP is applied to one input terminal of the voltage comparator 21.

For example, a triangular wave S is applied from a triangular wave generator 22 to the other input terminal of the voltage comparator 21. The DC component of the triangular wave S is the fourth
Assume that O as shown in figure A, the differential voltage Vi
If n −VNF = Q, the signal output from the voltage comparator 21 has a duty ratio of 50 as shown in FIG. 4B.
% rectangular wave P1.

When the differential voltage Vin -VNF becomes +E1, the voltage comparator 2
The output signal of 1 becomes a rectangular wave P2 in which the H logic state has a long period as shown in FIG. 4C. Also, the differential voltage Vin −
When VNF becomes -E2, the output signal of the voltage comparator 21 becomes a rectangular wave P3 in which the L logic state has a long period as shown in the fourth diagram.

These square wave signals P1. P2 or R3 as drive circuit 1
5, and Pl, R2 or R to the output of the 5 drive circuit 15.
The in-phase signals and anti-phase signals of 3 are output, and the in-phase signals and anti-phase signals are applied to switch elements 7A, 7D and 7C, 7B, respectively, to alternately apply positive and negative polarity voltages to the load circuit 11. give to If the duty ratio is 50, load circuit 1
Since the positive and negative DC voltages applied to the load 5 are applied for the same time, the positive and negative voltages cancel each other out, and no voltage is applied to the load 5. On the other hand, for example, if a rectangular wave P2 with a long H logic time is applied to the pair of switch elements 7C and 7B, and a rectangular wave P2 with a long L logic time is applied to a pair of switch elements 7A and 7D, the load circuit A positive voltage is applied to 11 for a longer time than a negative voltage. Therefore, a positive voltage is applied to the load 5. Conversely, if a rectangular wave with a long L logic time is applied to the pair of switch elements 7C and 7B, and a rectangular wave with a long H logic time is applied to the pair of switch elements 7A and 7D, the load circuit 1
1 is given a negative voltage from the power supply 6 for a longer period of time than the positive voltage, and therefore a negative voltage is given to the load 5 on average.

The voltage VOUT applied to the load 5 is determined by VOUT # d * Vin R3 when the resistance values of the resistors 17 and 18 are R, (, R3.

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 19.

"Operations and Effects of the Invention" As explained above, according to the present invention, the electromagnetic energy stored in the inductor 8 can be caused to flow through the capacitor 14.

Therefore, by selecting appropriate values for the on/off ratios of the switches 7A, 7D, 7C, and 7B, it is possible to apply a voltage of positive or negative polarity to the load circuit 11.

In addition, especially when increasing the absolute value of the voltage, or when decreasing the voltage, the back electromotive force of the inductor is
4, the response can be made faster.

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

[Brief explanation of drawings]

Fig. 1 is a connection diagram showing one embodiment of the present invention, Figs. 2 and 3 are waveform diagrams for explaining the operation of Fig. 1, and Fig. 4 is for explaining the operation of the voltage stabilizing circuit. waveform diagram, 5th
7 to 7 are connection diagrams for explaining the conventional technology. 5: Load, 6: DC power supply, 7A to 7D: Switch element,
8: Inductor, 9: Capacitor, llco load circuit, 1
4: Capacitor, 15: Gate drive circuit, 19: Deviation amplifier, 21: Voltage comparator.

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 bridge type switch circuit for alternately applying DC power supply voltage in opposite directions to this load circuit, and C: The above. A bipolar switching power supply consisting of a capacitor that is connected in parallel to a DC power supply and absorbs the back electromotive force generated in the above inductor.