Constant-current fast charging circuit, power supply device and testing machine

Abstract

The utility model relates to a constant-current fast charging circuit, a power supply device and a testing machine, the constant-current fast charging circuit comprises a power supply, a constant-current control module, a sampling element, a power tube and a charging element, the power supply is connected with a first end of the sampling element and the constant-current control module, and a second end of the sampling element is connected with an input end of the power tube; the constant-current control module is connected with the first end of the sampling element, the second end of the sampling element and the control end of the power tube; the output end of the power tube is connected with the charging element; the constant-current control module adjusts the power tube based on the charging current determined by the sampling element so as to carry out constant-current charging on the charging element, so that rapid charging of the charging element can be realized, the charging time is shortened, and the use convenience is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor testing, in particular to a constant-current fast charging circuit, a power supply device and a test machine. BACKGROUND

[0002] With the development of the new energy industry, the demand range of large current testing of power semiconductors is becoming larger and larger. As an indispensable part of integrated circuit ATE testing, VI source is used to provide test excitation for the device under test. The excitation source is to charge the large-capacity capacitor quickly through the power supply to meet the demand of large current testing. The traditional large-capacity capacitor charging device is to control the maximum charging current through the current limiting module, and then control the output voltage of the transistor module through the voltage dividing module, so as to finally control the charging current and charging voltage of the super capacitor. This charging method, the charging current will become smaller and smaller with the charging time, until the output voltage value controlled by the voltage dividing module, the charging time is relatively long and uncontrollable, and there is the shortcoming of low use convenience. CONTENT OF THE UTILITY MODEL

[0003] Therefore, it is necessary to provide a constant-current fast charging circuit, a power supply device and a test machine which can improve the use convenience in view of the above problems.

[0004] The first aspect of the present application provides a constant-current fast charging circuit, comprising a power supply, a constant-current control module, a sampling element, a power tube and a charging element, the power supply is connected to the first end of the sampling element and the constant-current control module, the second end of the sampling element is connected to the input end of the power tube, the constant-current control module is connected to the first end of the sampling element, the second end of the sampling element and the control end of the power tube, and the output end of the power tube is connected to the charging element; the constant-current control module adjusts the power tube based on the charging current determined by the sampling element to perform constant-current charging on the charging element.

[0005] In one of the embodiments, the constant-current control module comprises a current feedback loop and a voltage control loop, the current feedback loop is connected to the first end of the sampling element and the second end of the sampling element, and the voltage control loop is connected to the current feedback loop, the second end of the sampling element and the control end of the power tube.

[0006] In one of the embodiments, the current feedback loop comprises a switch tube and a resistor R2, the input end of the switch tube is connected to the first end of the sampling element, the control end of the switch tube is connected to the second end of the sampling element through the resistor R2, and the output end of the switch tube is connected to the voltage control loop.

[0007] In one of the embodiments, the voltage control loop comprises a resistor R3, a resistor R4 and a Zener diode, a first end of the resistor R3 is connected to a first end of the resistor R4 and an output end of the switch tube, a second end of the resistor R4 is grounded, a second end of the resistor R3 is connected to a control end of the power tube and an anode of the Zener diode, a cathode of the Zener diode is connected to a second end of the sampling element and an input end of the power tube.

[0008] In one of the embodiments, the switch tube is a triode.

[0009] In one of the embodiments, the power tube is a MOS tube.

[0010] In one of the embodiments, the power tube is a PMOS tube and the charging element is a charging capacitor; in the main loop formed by the sampling element, the PMOS tube and the charging capacitor, when the power is just turned on, the voltage across the charging capacitor is 0V due to the existence of the parasitic capacitance Cgs of the PMOS tube and the parasitic capacitance of the Zener diode, so the turn-on voltage Vgs of the PMOS tube is 0, thus the main loop is disconnected and the charging capacitor has no charging current; at the same time, the BE end voltage Vbe of the triode is 0, so the current flows through the sampling element, the Zener diode, the resistor R3 and the resistor R4 to the negative pole of the power supply at the initial stage of power-on; since the parasitic capacitance Cgs of the PMOS tube is very small, the parasitic capacitance voltage rises quickly, i.e. the voltage at the Vgs end of the PMOS tube rises, so that the PMOS tube is quickly turned on, the voltage at the Vgs end rises, the internal resistance Rds of the PMOS tube decreases, and the current of the main loop quickly rises to the charging current Iset value; when the actual charging current exceeds the charging current Iset value, the triode starts to conduct, the power supply reversely charges the parasitic capacitance Cgs of the PMOS tube through the triode and the resistor R3, so that the voltage at the Vgs end of the PMOS tube decreases, thereby controlling and adjusting the impedance of the PMOS tube to increase, reducing the current of the main loop, and finally reaching a balance and stabilizing at the charging current Iset value.

[0011] In one of the embodiments, the sampling element is a power resistor.

[0012] The second aspect of the present application provides a power supply device comprising the constant current fast charging circuit.

[0013] The third aspect of the present application provides a testing machine comprising the power supply device.

[0014] The constant current fast charging circuit, the power supply device and the testing machine, the constant current fast charging circuit comprises a power supply, a constant current control module, a sampling element, a power tube and a charging element, the constant current control module adjusts the power tube based on the charging current determined by the sampling element to perform constant current charging on the charging element, which can realize fast charging of the charging element, shorten the charging time and improve the use convenience. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The structure block diagram of the constant current fast charging circuit in one embodiment is shown in the figure.

[0016] Figure 2 The structure schematic diagram of the constant current fast charging circuit in one embodiment is shown in the figure. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0019] It can be understood that, in the following embodiments, “connection” between the circuits, modules, units, etc. connected to each other should be understood as “electrical connection”, “communication connection” and the like if there is transmission of electrical signals or data between them.

[0020] As used herein, the singular forms “a”, “an” and “the” can include plural forms unless the context clearly indicates otherwise. It should also be understood that the term “comprise / comprises” or “has / have” specifies the presence of stated features, integers, operations, components, parts or combinations thereof, but does not exclude the presence or addition of one or more other features, integers, operations, components, parts or combinations thereof.

[0021] In one embodiment, as shown in Figure 1 a constant current fast charging circuit is provided, including a power supply 110, a constant current control module 120, a sampling element 130, a power tube 140 and a charging element 150, the power supply 110 is connected to the first end of the sampling element 130 and the constant current control module 120, the second end of the sampling element 130 is connected to the input end of the power tube 140, the constant current control module 120 is connected to the first end of the sampling element 130, the second end of the sampling element 130 and the control end of the power tube 140, and the output end of the power tube 140 is connected to the charging element 150; the constant current control module 120 adjusts the power tube 140 based on the charging current determined by the sampling element 130 to perform constant current charging on the charging element 150.

[0022] As shown in Figure 2As shown, the power supply 110 can adopt a direct current power DC, the sampling element 130 can be a sampling resistor or other device, in the embodiment, the sampling element 130 is a power resistor R1. The power tube 140 can be a MOS tube or other switch tube, in the embodiment, the power tube 140 is a PMOS tube Q2, the gate G as the control end, the source S as the input end, and the drain D as the output end. The charging element 150 can be a charging capacitor or other charging device, in the embodiment, the charging element 150 is a large-capacity charging capacitor C1, the first end of the charging capacitor C1 is connected to the output end of the power tube 140, and the second end of the charging capacitor C1 is grounded. The resistance value of the power resistor R1 can be selected according to actual needs to set the charging current Iset value, and the constant current control module 120 controls the PMOS tube Q2 based on the charging current for negative feedback adjustment, so as to realize constant current charging of the charging capacitor C1, achieve fast charging, and the charging time is controllable.

[0023] In one embodiment, the constant current control module 120 includes a current feedback loop 122 and a voltage control loop 124, the current feedback loop 122 is connected to the first end of the sampling element 130 and the second end of the sampling element 130, and the voltage control loop 124 is connected to the current feedback loop 122, the second end of the sampling element 130 and the control end of the power tube 140.

[0024] Specifically, the current feedback loop 122 includes a switch tube Q1 and a resistor R2, the input end of the switch tube Q1 is connected to the first end of the sampling element 130, the control end of the switch tube Q1 is connected to the second end of the sampling element 130 through the resistor R2, and the output end of the switch tube Q1 is connected to the voltage control loop 124. The switch tube Q1 can be a triode or other type of controlled switch, in the embodiment, the switch tube Q1 is a PNP triode, the base B as the control end, the emitter E as the input end, and the collector C as the output end.

[0025] Further, the voltage control loop 144 can include a resistor R3, a resistor R4 and a voltage stabilizing tube Z1, the first end of the resistor R3 is connected to the first end of the resistor R4 and the output end of the switch tube Q1, the second end of the resistor R4 is grounded, the second end of the resistor R3 is connected to the control end of the power tube 140 and the anode of the voltage stabilizing tube Z1, and the cathode of the voltage stabilizing tube Z1 is connected to the second end of the sampling element 130 and the input end of the power tube 140. The resistor R3 can be a resistor with a fixed resistance value, or a resistor with an adjustable resistance value. In the embodiment, the resistor R3 is a resistor with an adjustable resistance value, for example, the resistance value of the resistor R3 can be set to 0 ohm or K ohm, and the specific value can be adjusted according to actual needs.

[0026] The above constant current fast charging circuit sets the charging current through the power resistor R1, and the current feedback loop 122 and the voltage control loop 124 jointly act on the power tube 140 to realize constant current charging control of the charging capacitor C1. The charging current Iset = Vbe R1 (R1 is the power resistance value), Vbe≈0.7V, depending on the model of switch tube Q1. The charging current can be set by adjusting the resistance value of power resistor R1, and the charging current of charging capacitor C1 is adjusted.

[0027] In the main circuit composed of power resistor R1, PMOS tube Q2 and charging capacitor C1, when the power is just on, due to the existence of the parasitic capacitance Cgs of PMOS tube Q2 and the parasitic capacitance of Zener Z1, the voltage across the charging capacitor C1 is 0V, and the opening voltage Vgs of PMOS tube Q2 is 0, so the main circuit is disconnected, and the charging capacitor C1 has no charging current. At the same time, since the voltage V be =0, so at the initial power-on, the current flows through the power resistor R1, the Zener Z1, the resistor R3 and the resistor R4 to the negative pole of the DC power supply. Since the parasitic capacitance Cgs of PMOS tube Q2 is very small, the parasitic capacitance voltage rises quickly, that is, the Vgs voltage of PMOS tube Q2 rises, so that PMOS tube Q2 quickly opens, the Vgs voltage rises, the internal resistance Rds of PMOS tube Q2 decreases, and the current of the main circuit quickly rises to the charging current Iset value. When the actual charging current exceeds the charging current Iset value, that is, Vbe>0.7V, the switch tube Q1 starts to conduct, the DC power supply charges the parasitic capacitance Cgs of PMOS tube Q2 in reverse through the switch tube Q1 and the resistor R3, so that the Vgs voltage of PMOS tube Q2 decreases, and then the impedance of PMOS tube Q2 is increased to control and adjust, the current of the main circuit is reduced, and finally the balance is reached, and the charging current Iset value is stabilized.

[0028] In the voltage feedback loop 144 formed by the voltage stabilizing tube Z1, the resistor R3 and the resistor R4, the voltage Vgs at the GS end of the PMOS tube Q2 is mainly controlled to adjust the resistance Rds at the DS end of the PMOS tube Q2, thereby controlling the current of the main circuit. When the voltage Vgs increases, the resistance Rds of the PMOS tube Q2 decreases, and when the voltage Vgs decreases, the resistance Rds of the PMOS tube Q2 increases. The resistor R3 and the resistor R4 are voltage dividing resistors, providing a static working point. When the voltage fluctuates, the voltage Vgs of the PMOS tube Q2 does not exceed the limit, and the MOS tube is protected. When the power is first turned on, the voltage Vgs = 0 (due to the existence of the parasitic capacitor Cgs), and a static working point is set by the voltage division of the resistor R3 and the resistor R4. When the voltage Vgs rises during the current rising process, the PMOS tube Q2 is turned on, the resistance of the PMOS tube Q2 decreases, the current rises rapidly, and the current charges the charging capacitor C1. When the current rises and exceeds the charging current Iset value, the switch tube Q1 is turned on, the power supply charges the parasitic capacitor Cgs of the PMOS tube through the transistor and the resistor R3, thereby reducing the voltage Vgs, increasing the resistance of the PMOS tube Q2, reducing the main circuit current, and finally balancing the voltage Vgs, stabilizing the resistance of the PMOS tube Q2, and stabilizing the output of the main circuit to the charging current Iset value.

[0029] According to the characteristics of the PMOS tube Q2, the voltage Vgs of the PMOS tube Q2 is controlled to control the resistance Rds at the DS end of the PMOS tube Q2, thereby adjusting the stability of the main circuit current. Based on the capacity C of the charging capacitor C1, the charging current I and the charging voltage V, the charging time t value can be calculated according to I*t = C*V, so that the constant current fast charging circuit works in a reasonable condition, for example, the charging and discharging of the charging capacitor C1 is controlled according to the charging time t.

[0030] In summary, the constant current fast charging circuit forms a negative feedback system for the power tube 140 through the current feedback loop 122 and the voltage feedback loop 124, thereby achieving the purpose of constant current control. By adjusting the resistance value of the power resistor R1, the charging current of the charging capacitor C1 can be set. In addition, the power tube 140 has small resistance and large current capacity, which can set large current constant current charging to meet the practical application requirements of fast charging. The constant current fast charging circuit has the following advantages:

[0031] 1. Large current charging can be achieved. The design of the voltage-controlled power MOS tube has small resistance and large current capacity, which can greatly improve the current value of the constant current charging.

[0032] 2. Large capacity capacitor fast charging can be achieved. Through the design of the current feedback loop and the voltage feedback loop, a large current constant current circuit is designed, thereby realizing the fast charging of the capacitor.

[0033] 3. Controllable charging time. The constant current charging circuit design can calculate the charging time according to the formula I*t=C*V.

[0034] 4. Self-protection function. The design of the voltage stabilizing tube protecting the power MOS tube and the feedback loop can automatically shut off the MOS tube in the case of overcurrent, thereby protecting the entire loop.

[0035] 5. Soft start function. The self parasitic capacitance of the voltage stabilizing tube and the MOS tube can ensure that the current slowly rises when the entire circuit is powered on, without current overshoot.

[0036] In one embodiment, a power supply device including the constant current fast charging circuit described above is also provided. The power supply device can be a VI (voltage current) source in particular.

[0037] In one embodiment, a test machine including the power supply device described above is also provided.

[0038] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but it should be understood that any combination of the technical features that does not cause contradiction is within the scope of the present disclosure.

[0039] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the utility model patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A constant current fast charging circuit, characterized in that, The constant current control module is connected with the first end of the sampling element, the second end of the sampling element and the control end of the power tube. The constant current control module adjusts the power tube based on the charging current determined by the sampling element to perform constant current charging on the charging element.

2. The circuit of claim 1, wherein, The constant current control module comprises a current feedback loop and a voltage control loop.

3. The circuit of claim 2, wherein, The current feedback loop comprises a switch tube and a resistor R2.

4. The circuit of claim 3, wherein, The voltage control loop comprises a resistor R3, a resistor R4 and a zener diode.

5. The circuit of claim 4, wherein, The switch tube is a triode.

6. The circuit of claim 5, wherein, The power tube is a MOS tube.

7. The circuit of claim 6, wherein, The power tube is a PMOS tube, and the charging element is a charging capacitor.

8. The circuit of any one of claims 1-7, wherein, The main loop formed by the sampling element, the PMOS tube and the charging capacitor is disconnected at the initial power-on, and the charging capacitor has no charging current.

9. A power supply device characterized by comprising: The sampling element is a power resistor.

10. A testing machine characterized by, The constant current fast charging circuit of any one of claims 1-8. The power supply device of claim 9.

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