CN-115864566-B - MLCC capacitive test power supply output bidirectional current limiting circuit

CN115864566BCN 115864566 BCN115864566 BCN 115864566BCN-115864566-B

Abstract

The invention discloses an MLCC capacitor test power output bidirectional current limiting circuit which comprises an electric power module, a DAC output module circuit, a first filter capacitor, a second filter capacitor, an operational amplifier comparator output driving circuit, a first isolation diode, a second isolation diode, a first current limiting resistor, a second current limiting resistor, a third current limiting resistor, a fourth current limiting resistor, a quick turn-off circuit, a clamp protection diode circuit, a current limiting switch circuit and a current limiting sampling circuit, wherein the electric power module comprises a positive power module and a negative power module. In the invention, the output of the test power supply has both the forward charging current limiting function and the reverse charging current limiting function, and the charging current limiting current parameter value of the load to be tested can be freely adjusted and set, so that the test power supply is convenient to be used for various MLCC capacitors. The technical scheme provided by the invention also has the capability of rapidly switching off the current-limiting switch, can improve the output safety and reliability of the test power supply, reduces the cost and is convenient for wide use.

Inventors

LIAO SHENGJIAN
LIU DONG
LI YANGYUN
MA ZONGHUA
LI AIZHEN
SONG DUAN
DENG YONG

Assignees

珠海禅光科技有限公司

Dates

Publication Date: 20260505
Application Date: 20221117

Claims (8)

1. The MLCC capacitor test power supply output bidirectional current limiting circuit is characterized by comprising a power supply module, a DAC output module circuit, a first filter capacitor, a second filter capacitor, an operational amplifier comparator output driving circuit, a first isolation diode, a second isolation diode, a first current limiting resistor, a second current limiting resistor, a third current limiting resistor, a fourth current limiting resistor, a quick turn-off circuit, a clamp protection diode circuit, a current limiting switch circuit and a current limiting sampling circuit, wherein the power supply module comprises a positive power supply module and a negative power supply module; the DAC output module is connected with the operational amplifier comparator output driving circuit; The operational amplifier comparator output driving circuit is connected with the DAC output module, the isolation diode, the quick turn-off circuit and the current-limiting sampling circuit; The first isolation diode and the second isolation diode are connected with an output driving circuit of the operational amplifier comparator and a quick turn-off circuit; The fast turn-off circuit is connected with the output driving circuit of the operational amplifier comparator, the isolation diode and the current-limiting switch circuit; The clamping protection diode circuit is arranged between the fast turn-off circuit and the path of the current-limiting switch circuit; The current-limiting switch circuit is connected with the positive and negative power supply modules and the current-limiting sampling circuit; the current-limiting sampling circuit is connected with the current-limiting switching circuit and the output driving circuit of the operational amplifier comparator; The output driving circuit of the operational amplifier comparator comprises a first operational amplifier and a second operational amplifier, wherein the pins of the first operational amplifier comprise a first pin, a second pin, a third pin, a fourth pin and an eighth pin; The first pin is connected with the anode of the first isolation diode, the second pin is connected with the third current limiting resistor, the third pin is connected with the common connection end of the first filter capacitor and the DAC output module circuit, the fourth pin is connected with the cathode of the power supply of the operational amplifier, the eighth pin is connected with the anode of the power supply of the operational amplifier, and the first operational amplifier is used for driving the current limiting switch circuit during forward charging; The fifth pin is connected with the common connection end of the second filter capacitor and the DAC output module circuit, the sixth pin is connected with the fourth current limiting resistor, the seventh pin is connected with the anode of the second isolation diode, and the second operational amplifier is used for driving the current limiting switch circuit during reverse charging.
2. The MLCC capacitance test power output bi-directional current limiting circuit of claim 1, wherein said power module comprises a current limiting protection power supply, a positive and negative power module input, a positive and negative power module output, an operational amplifier power supply, a DC power supply, wherein: The current-limiting protection power supply is referenced to the ground plane in potential; The positive and negative power supply output ends are referenced to the ground plane in potential; The current-limiting protection power supply and the positive and negative power supply output ends are mutually isolated.
3. The MLCC capacitive test power supply output bi-directional current limiting circuit of claim 1, wherein the DAC output module circuit is configured to control a DAC function by a control unit, output a settable voltage by a PWM analog DAC chip function, or by a dedicated DAC chip, the settable voltage being configured to adjust a current value of a load under test MLCC capacitor charging current limiting.
4. The MLCC capacitance test power supply output bidirectional current limiting circuit of claim 2, wherein an anode of the first isolation diode is connected with a first pin of the first operational amplifier, a cathode of the first isolation diode is connected with the first current limiting resistor, an anode of the second isolation diode is connected with a seventh pin of the second operational amplifier, and a cathode of the first isolation diode is connected with the second current limiting resistor.
5. The MLCC capacitance test power output bidirectional current limiting circuit of claim 4, wherein the quick turn-off circuit comprises a first quick turn-off circuit and a second quick turn-off circuit, the first quick turn-off circuit comprises a first resistor, a second resistor and a first quick turn-off circuit three-terminal semiconductor, one end of the first resistor is connected with a common connection end of a first pin of the first operational amplifier and an anode of the first isolation diode, the other end of the first resistor is connected with a grid electrode of the first quick turn-off circuit three-terminal semiconductor, a source electrode of the first quick turn-off circuit three-terminal semiconductor is connected with the first current limiting resistor, a drain electrode of the first quick turn-off circuit three-terminal semiconductor is connected with the second resistor, and the other end of the second resistor is connected with a current limiting protection power supply; The second quick turn-off circuit comprises a third resistor, a fourth resistor and a second quick turn-off circuit three-terminal semiconductor, one end of the third resistor is connected with a common connection end of a seventh pin of the second operational amplifier and an anode of the second isolation diode, the other end of the third resistor is connected with a grid electrode of the second quick turn-off circuit three-terminal semiconductor, a source electrode of the second quick turn-off circuit three-terminal semiconductor is connected with the second current limiting resistor, a drain electrode of the second quick turn-off circuit three-terminal semiconductor is connected with the fourth resistor, and the other end of the fourth resistor is connected with a current limiting protection power supply.
6. The MLCC capacitance test power supply output bidirectional current limiting circuit of claim 5, wherein the clamp protection diode circuit comprises a first clamp protection diode circuit and a second clamp protection diode circuit, the first clamp protection diode circuit comprises a first protection diode and a second protection diode, the anode of the first protection diode is connected with a common connection end of the source electrode of the three-terminal semiconductor of the first quick turn-off circuit and the first current limiting resistor, the cathode of the first protection diode is connected with a direct current power supply, the anode of the second protection diode is connected with the current limiting protection power supply, and the cathode of the second protection diode is connected with the common connection end of the source electrode of the three-terminal semiconductor of the first quick turn-off circuit and the first current limiting resistor; The second clamping protection diode circuit comprises a third protection diode and a fourth protection diode, wherein the anode of the third protection diode is connected with a common connection end of the source electrode of the three-end semiconductor of the second quick turn-off circuit and the second current limiting resistor, the cathode of the third protection diode is connected with a direct current power supply, the anode of the fourth protection diode is connected with the current limiting protection power supply, and the cathode of the fourth protection diode is connected with the common connection end of the source electrode of the three-end semiconductor of the second quick turn-off circuit and the second current limiting resistor.
7. The MLCC capacitance test power supply output bidirectional current limiting circuit of claim 6, wherein the current limiting switch circuit comprises a first current limiting switch circuit and a second current limiting switch circuit, the first current limiting switch circuit comprises a first current limiting switch circuit MOS tube, the grid electrode of the first current limiting switch circuit MOS tube is connected with the common connection end of the source electrode of the three-terminal semiconductor of the first quick turn-off circuit and the first current limiting resistor, the source electrode of the first current limiting switch circuit MOS tube is connected with the common connection end of the first sampling resistor and the first current limiting sampling resistor, and the drain electrode of the first current limiting switch circuit MOS tube is connected with the positive and negative power supply module output end; the grid electrode of the second current-limiting switch circuit MOS tube is connected with the common connecting end of the second current-limiting resistor, the source electrode of the second current-limiting switch circuit MOS tube is connected with the common connecting end of the second sampling resistor and the second current-limiting sampling resistor, and the drain electrode of the second current-limiting switch circuit MOS tube is connected with a load to be tested.
8. The MLCC capacitor test power supply output bidirectional current limiting circuit of claim 7, wherein the current limiting sampling circuit comprises a first current limiting sampling circuit and a second current limiting sampling circuit, the first current limiting sampling circuit comprises a third current limiting resistor and a first sampling resistor, one end of the third current limiting resistor is connected with a common connection end of a source electrode of a MOS tube of the first current limiting switch circuit and the first sampling resistor, and the other end of the third current limiting resistor is connected with a second pin of a first operational amplifier; The second current-limiting sampling circuit comprises a fourth current-limiting resistor and a second sampling resistor, one end of the fourth current-limiting resistor is connected with a common connection end of an MOS tube source electrode of the second current-limiting switch circuit and the second sampling resistor, and the other end of the fourth current-limiting resistor is connected with a sixth pin of the second operational amplifier; The first current-limiting sampling circuit is used for sampling forward charging current, and the second current-limiting sampling circuit is used for sampling reverse charging current.

Description

MLCC capacitive test power supply output bidirectional current limiting circuit Technical Field The invention relates to the field of electronic application technology and capacitance test, in particular to a two-way current limiting circuit for MLCC capacitance test power supply output. Background MLCC (Multi-LAYER CERAMIC Capacitors) is an English abbreviation for chip multilayer ceramic capacitor. The ceramic dielectric films with electrodes (inner electrodes) printed are overlapped in a dislocation mode, a ceramic chip is formed through one-time high-temperature sintering, and metal layers (outer electrodes) are sealed at two ends of the chip, so that a monolithic-like structure body is formed, and the monolithic capacitor is also called. MLCC capacitors are widely used, and the consumer electronics field is dominant. The MLCC capacitor device terminal market mainly covers the fields of mobile phones, audio and video equipment, computers, automobiles, other industries, medical treatment and the like. The demand of the MLCC capacitor is gradually increased, the yield is increased, and whether the MLCC capacitor has defective products, how the reliability is, performance, withstand voltage and other series problems exist. Manufacturers can test MLCC capacitors after the MLCC capacitors are produced and the MLCC capacitors are positively charged and reversely charged by using an MLCC capacitor test power supply, so that various performances are met and the MLCC capacitors can be used by leaving factories. In order to ensure the test safety of the MLCC capacitor, the charging process of the MLCC capacitor must be limited, so as to prevent the MLCC capacitor to be measured from being damaged due to overlarge current or prevent the MLCC capacitor to be measured from being damaged due to poor short circuit, thereby causing the output current of the MLCC capacitor test power supply to be increased sharply. Most of the current MLCC capacitor test power supplies in the market are single in output current limiting direction, the number of test stations is increased, the process is complex, the components are numerous, the price is high, the forward charging and directional charging bidirectional current limiting protection function of the MLCC capacitor can be met, and the current limiting protection device is difficult to widely apply. Thus, there is a need for a solution to the problems of the prior art. Disclosure of Invention The invention aims to provide a bidirectional current limiting circuit, a solution and a technical scheme for the output of an MLCC capacitor test power supply, which are convenient for being widely applied to various MLCC capacitor test power supplies, improve the output safety and reliability of the test power supply, reduce the cost and are convenient for wide use. The invention provides an MLCC capacitor test power output bidirectional current limiting circuit, which comprises a power module, a DAC output module circuit, a first filter capacitor, a second filter capacitor, an operational amplifier comparator output driving circuit, a first isolation diode, a second isolation diode, a first current limiting resistor, a second current limiting resistor, a third current limiting resistor, a fourth current limiting resistor, a quick turn-off circuit, a clamp protection diode circuit, a current limiting switch circuit and a current limiting sampling circuit, wherein the power module comprises a positive power module and a negative power module; the DAC output module is connected with the operational amplifier comparator output driving circuit; The operational amplifier comparator output driving circuit is connected with the DAC output module, the isolation diode, the quick turn-off circuit and the current-limiting sampling circuit; the isolation diode is connected with an output driving circuit of the operational amplifier comparator and a quick turn-off circuit; The fast turn-off circuit is connected with the output driving circuit of the operational amplifier comparator, the isolation diode and the current-limiting switch circuit; The clamping protection diode circuit is arranged between the fast turn-off circuit and the path of the current-limiting switch circuit; The current-limiting switch circuit is connected with the positive and negative power supply modules and the current-limiting sampling circuit; the current-limiting sampling circuit is connected with the current-limiting switching circuit and the output driving circuit of the operational amplifier comparator. Further, the power module comprises a current-limiting protection direct current power supply, a positive and negative power module input end, a positive and negative power module output end, an operational amplifier power supply and a direct current power supply, and the characteristics of various power supplies are as follows: The current-limiting protection power supply is referenced to the ground plane in potential; T