A combined power input high-voltage bus soft start protection circuit and combined power supply

By introducing a combination design of blocking unit, soft start control unit and current limiting resistor into the combined power supply, the problem of power switch damage caused by rapid voltage change of bus capacitor is solved, and the stability and reliability of the combined power supply are improved in complex environments.

CN224596364UActive Publication Date: 2026-08-04CETC XIAN NAVIGATION TECH CO LTD
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Patent Information

Application Number
CN202522004378.5
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2025-09-17
Publication Date
2026-08-04
Estimated Expiration
2035-09-17

AI Technical Summary

Technical Problem

The existing soft-start circuit design causes the bus capacitor to generate a large instantaneous current when the DC input voltage changes rapidly, which damages the power switching transistors and affects the reliability and stability of the combined power supply.

Method used

The design employs a combination of blocking unit, slow-start control unit, bus discharge unit and current-limiting resistor. By blocking the discharge circuit of the bus capacitor, the conduction of the power switch is delayed, and the charging current is carried by the current-limiting resistor to prevent the power switch from being damaged by overpower.

Benefits of technology

It effectively suppresses instantaneous high current, improves the reliability and stability of the circuit under complex power supply conditions, and ensures the stable operation of the combined power supply in complex environments.

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Abstract

This application discloses a combined power supply input high-voltage bus soft-start protection circuit and a combined power supply. The first terminal of the blocking unit D1 is connected to the positive terminal of the DC input terminal V1. The positive terminal of the bus capacitor C2 is connected to the second terminal of the blocking unit D1, and the negative terminal is connected to the drain of the power switch Q1. The soft-start control unit includes a first resistor R1, a second resistor R2, and a soft-start capacitor C1. The first terminal of the first resistor R1 is connected to the positive terminal of the DC input terminal V1, and its second terminal is connected to the gate of the power switch Q1, and branched to connect the second resistor R2 and the first terminal of the soft-start capacitor C1. The second terminals of the second resistor R2 and the soft-start capacitor C1 are both connected to the source of the power switch Q1. The bus discharge unit R4 is connected in parallel across the bus capacitor C2. The current-limiting resistor R is connected in parallel between the source and drain of the power switch Q1. When the DC input terminal V1 is rapidly powered on, this application effectively suppresses the instantaneous large current flowing through the power switch Q1, preventing it from being damaged due to overpower.
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