IGBT control circuit with soft start protection function

Abstract

An IGBT control circuit with soft start protection function, comprising: an input end connected with the base of a transistor Q7, the emitter of which is grounded, and the collector of which is connected with a starting voltage, and the input end is also connected with an IGBT tube; a transistor Q1, the base of which is connected with the collector of the transistor Q7, the emitter of which is grounded through a capacitor C19, and the collector of which is connected with the starting voltage; a transistor Q5, the base of which is connected with a starting signal and the starting voltage, the emitter of which is grounded, and the collector of which is connected with the starting voltage; a transistor Q2, the base of which is connected with the starting voltage, the emitter of which is connected with the control end of the IGBT tube, and the collector of which is connected with the starting voltage; a transistor Q3, the base of which is connected with the starting voltage, the emitter of which is connected with the control end of the IGBT tube, and the collector of which is connected with the emitter of the transistor Q2; and a transistor Q6, the base of which is connected with the starting voltage, the collector of which is grounded, and the emitter of which is connected with the collector of the transistor Q3.

Description

Technical Field

[0001] This utility model relates to the field of heating cookware circuits, and in particular to an IGBT control circuit with soft-start protection function. Background Technology

[0002] In IGBT control circuits, a transistor push-pull circuit is commonly used as an electronic switch to drive the IGBT. In this switching circuit, two transistors work alternately: one connects the circuit to +18V, and the other connects it to ground. The gate (G) of the IGBT driver circuit board is switched on and off via the PPG pin of the main chip. However, current industry solutions do not perform a soft start before the IGBT is turned on; instead, the 18V is turned on or off instantaneously. The peak current at the moment the IGBT is turned on is very high (far exceeding the peak current range of the IGBT), causing the IGBT to overheat and be damaged. This can lead to quality issues such as short circuits, tripping, and fires in the entire device due to IGBT failure. Utility Model Content

[0003] To address the aforementioned issues, this technical solution provides an IGBT control circuit with soft-start protection.

[0004] To achieve the above objectives, the technical solution is as follows:

[0005] An IGBT control circuit with soft-start protection function includes:

[0006] The input terminal is connected to the base of transistor Q7, the emitter is grounded, and the collector is connected to a startup voltage. The input terminal is also connected to an IGBT transistor.

[0007] Transistor Q1 has its base connected to the collector of transistor Q7, its emitter grounded through capacitor C19, and its collector connected to the startup voltage.

[0008] Transistor Q5 has a base connected to a start signal and is also connected to the start voltage. Its emitter is grounded and its collector is connected to the start voltage.

[0009] Transistor Q2 has its base connected to the startup voltage, its emitter connected to the control terminal of the IGBT, and its collector connected to the startup voltage.

[0010] Transistor Q3 has its base connected to the startup voltage, its emitter connected to the control terminal of the IGBT, and its collector connected to the emitter of transistor Q2.

[0011] Transistor Q6 has its base connected to the startup voltage, its collector grounded, and its emitter connected to the collector of transistor Q3.

[0012] In some embodiments, the input terminal is grounded in sequence through resistors R16, R17, R18, R19, R20, R39, R44 and R48, and the common connection point between resistors R44 and R48 is connected to the base of transistor Q7 through resistor R49.

[0013] In some embodiments, the base of the transistor Q5 is connected to the start signal via resistor R34, and resistor R34 is also connected to the start voltage via resistor R29.

[0014] In some embodiments, the base of transistor Q1 is connected to the collector of transistor Q7 via diode D10 and resistor R53 in sequence, the emitter of transistor Q1 is connected to capacitor C19 via resistor R33, and the emitter is also connected to the base of transistor Q6, and the collector of transistor Q1 is connected to the start-up voltage via resistor R54.

[0015] In some embodiments, the base of transistor Q2 is connected to the startup voltage via resistor R10, the collector is connected to the startup voltage via resistor R23, and the emitter is connected to the emitter of transistor Q6 via resistor R24.

[0016] In some embodiments, the base of transistor Q3 is grounded through resistor R32, and the base is also connected to the startup voltage through resistor R25. The collector is connected to transistor Q6, and the emitter is connected to the IGBT in sequence through diode D11, ferrite bead B1, and resistor R58.

[0017] In some embodiments, the resistor R58 is grounded through the resistor R28 and the Zener diode ZD1.

[0018] The beneficial effects of this application are:

[0019] This application implements a soft start before the boiler test and start-up of the IGBT, which effectively prevents the risk of IGBT overheating and damage caused by excessive peak current at the moment the IGBT turns on during the boiler test and start-up heating. This greatly improves the service life of the IGBT and avoids quality hazards such as short circuit tripping and fire caused by IGBT damage to the whole machine. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0021] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model;

[0022] Figure 2 This is a schematic diagram of the standby idle state waveform of an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the waveforms of the pot inspection and heating start-up states according to an embodiment of this utility model;

[0024] Figure 4 This is a schematic diagram of the normal heating state waveform of an embodiment of this utility model. Detailed Implementation

[0025] To make the technical problems solved, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0026] Please refer to Figure 1-4 As shown, an IGBT control circuit with soft-start protection function includes:

[0027] The input terminal is connected to the base of transistor Q7, the emitter is grounded, and the collector is connected to a startup voltage. The input terminal is also connected to an IGBT transistor.

[0028] Transistor Q1 has its base connected to the collector of transistor Q7, its emitter grounded through capacitor C19, and its collector connected to the startup voltage.

[0029] Transistor Q5 has a base connected to a start signal and is also connected to the start voltage. Its emitter is grounded and its collector is connected to the start voltage.

[0030] Transistor Q2 has its base connected to the startup voltage, its emitter connected to the control terminal of the IGBT, and its collector connected to the startup voltage.

[0031] Transistor Q3 has its base connected to the startup voltage, its emitter connected to the control terminal of the IGBT, and its collector connected to the emitter of transistor Q2.

[0032] Transistor Q6 has its base connected to the startup voltage, its collector grounded, and its emitter connected to the collector of transistor Q3.

[0033] refer to Figure 2At point D, the voltage is 311V and at point E, the voltage is 0.76V. At this time, transistor Q7 is turned on, the voltage at point F is 0V, and transistor Q1 is turned off. At point A, the voltage is 2V, transistor Q5 is turned on, the voltage at point B is 0V, transistor Q2 is turned off, and the voltage at point C is 0V, and the IGBT is off.

[0034] refer to Figure 3 (1) When the voltage at point A drops for the first time, transistor Q5 turns off, and 18V charges C19 through R10 and R33. The voltage at point B gradually rises, transistor Q2 turns on, and the voltage at point C also rises. (2) When the voltage at point C is 9V, the voltage at point H is 8V. Transistors Q3 and Q6 turn on and conduct, the voltage rise at point C slows down, the IGBT turns on, the coil is charged, and the voltages at points D and E gradually decrease. (3) After 4us, the voltage at point A rises, the drive circuit returns to the idle state, and the IGBT has been soft-started. (4) The voltage at point D is close to 0. The voltage at point A is pulled down for the second time, transistor Q5 is turned off, and the voltage at point E drops to the point that Q7 is turned off. The voltage at point F rises, Q1 is turned on, and 18V charges C19 through R10, R54, and R33. At this time, the charging is faster than the first time. Point C can be charged to 18V, the IGBT is fully turned on, and the coil continues to store energy. (5) After 4us, the voltage at point A is pulled up, and the drive circuit returns to the idle state. At this time, the coil has stored energy and can perform pot inspection and start heating operations.

[0035] refer to Figure 4 When the voltage at point A is pulled low, transistors Q5 and Q7 are turned off in time, and the voltage at point C can quickly rise to 18V.

[0036] In summary, this solution optimizes the IGBT drive design, ensuring that the IGBT is soft-started before the boiler check and start-up. This effectively prevents the risk of IGBT overheating and damage caused by excessive peak current during the first waveform of boiler check and heating start-up. This significantly improves the lifespan of the IGBT and avoids quality hazards such as short circuits, tripping, and fires caused by IGBT damage.

[0037] In some embodiments, the input terminal is grounded in sequence through resistors R16, R17, R18, R19, R20, R39, R44 and R48, and the common connection point between resistors R44 and R48 is connected to the base of transistor Q7 through resistor R49.

[0038] In some embodiments, the base of the transistor Q5 is connected to the start signal via resistor R34, and resistor R34 is also connected to the start voltage via resistor R29.

[0039] In some embodiments, the base of transistor Q1 is connected to the collector of transistor Q7 via diode D10 and resistor R53 in sequence, the emitter of transistor Q1 is connected to capacitor C19 via resistor R33, and the emitter is also connected to the base of transistor Q6, and the collector of transistor Q1 is connected to the start-up voltage via resistor R54.

[0040] In some embodiments, the base of transistor Q2 is connected to the startup voltage via resistor R10, the collector is connected to the startup voltage via resistor R23, and the emitter is connected to the emitter of transistor Q6 via resistor R24.

[0041] In some embodiments, the base of transistor Q3 is grounded through resistor R32, and the base is also connected to the startup voltage through resistor R25. The collector is connected to transistor Q6, and the emitter is connected to the IGBT in sequence through diode D11, ferrite bead B1, and resistor R58.

[0042] In some embodiments, the resistor R58 is grounded through the resistor R28 and the Zener diode ZD1.

[0043] The above description is only a preferred embodiment of this application and is not intended to limit the scope of implementation of this application. Any other embodiments whose principles and basic structures are the same as or similar to those of this application are within the protection scope of this application.

Claims

1. An IGBT control circuit with soft-start protection function, characterized in that, include; The input terminal is connected to the base of transistor Q7, the emitter is grounded, and the collector is connected to a startup voltage. The input terminal is also connected to an IGBT transistor. Transistor Q1 has its base connected to the collector of transistor Q7, its emitter grounded through capacitor C19, and its collector connected to the startup voltage. Transistor Q5 has a base connected to a start signal and is also connected to the start voltage. Its emitter is grounded and its collector is connected to the start voltage. Transistor Q2 has its base connected to the startup voltage, its emitter connected to the control terminal of the IGBT, and its collector connected to the startup voltage. Transistor Q3 has its base connected to the startup voltage, its emitter connected to the control terminal of the IGBT, and its collector connected to the emitter of transistor Q2. Transistor Q6 has its base connected to the startup voltage, its collector grounded, and its emitter connected to the collector of transistor Q3.

2. The IGBT control circuit with soft-start protection function according to claim 1, characterized in that: The input terminal is grounded in sequence through resistors R16, R17, R18, R19, R20, R39, R44 and R48. The common connection point between resistors R44 and R48 is connected to the base of transistor Q7 through resistor R49.

3. The IGBT control circuit with soft-start protection function according to claim 1, characterized in that: The base of the transistor Q5 is connected to the start signal through resistor R34, and resistor R34 is also connected to the start voltage through resistor R29.

4. The IGBT control circuit with soft-start protection function according to claim 1, characterized in that: The base of transistor Q1 is connected to the collector of transistor Q7 via diode D10 and resistor R53. The emitter of transistor Q1 is connected to capacitor C19 via resistor R33. The emitter is also connected to the base of transistor Q6. The collector of transistor Q1 is connected to the start-up voltage via resistor R54.

5. The IGBT control circuit with soft-start protection function according to claim 1, characterized in that: The base of transistor Q2 is connected to the startup voltage through resistor R10, the collector is connected to the startup voltage through resistor R23, and the emitter is connected to the emitter of transistor Q6 through resistor R24.

6. The IGBT control circuit with soft-start protection function according to claim 1, characterized in that: The base of transistor Q3 is grounded through resistor R32, and the base is also connected to the start-up voltage through resistor R25. The collector is connected to transistor Q6, and the emitter is connected to IGBT transistor in sequence through diode D11, ferrite bead B1, and resistor R58.

7. The IGBT control circuit with soft-start protection function according to claim 6, characterized in that: The resistor R58 is grounded through resistor R28 and Zener diode ZD1.

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