High-low voltage constant current source system

Abstract

The utility model discloses a high-low voltage constant current source system which comprises a high-voltage direct current battery pack, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a resistor R5. A diode D1, a diode D2, a diode D3, a diode D4, a diode D6 and a diode D7; a triode Q1, a triode Q2, a triode Q3, and a bidirectional voltage-regulator tube TV1, a bidirectional voltage-regulator tube TV2, a bidirectional voltage-regulator tube TV3, and a bidirectional voltage-regulator tube TV4; the high-voltage direct-current battery pack is provided with an upper positive electrode and a lower negative electrode, the positive electrode is connected with one end of the resistor R1, the other end of the resistor R1 is connected with the anode of the diode D1 and the resistor R2, the diode D1 and the diode D2 are connected in series and connected with the resistor R2 in parallel, and the cathode of the diode D2 is connected with the bidirectional voltage-regulator tube TV1, the bidirectional voltage-regulator tube TV2 and the bidirectional voltage-regulator tube TV3 in series and connected with the negative electrode of the battery pack. According to the utility model, personnel mistaken touch caused by the fact that the high-voltage energy storage device cannot discharge quickly due to power failure can be prevented; the circuit has the advantages of simple structure, few types of required devices, low cost and wide voltage coverage range, and supports anti-reverse connection design.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, and in particular to a high and low voltage constant current source system that can meet different voltage levels. Background Technology

[0002] With the rapid development of new energy vehicles in China, the voltage platform of these vehicles has increased to meet the demands for driving and fast charging. During production and maintenance, after the high-voltage battery pack is disconnected, the control board often fails to discharge voltage for a period of time due to the lack of energy-consuming loads in energy storage devices such as film capacitors, and there are no obvious warning signs. This could potentially lead to electric shock. Chinese patents CN214544244U and CN113162563A disclose a DC high-voltage power amplifier system, but both suffer from the following problems: the withstand voltage cannot meet the requirements of existing vehicle power supplies; the types of components used are complex, and meeting high voltage requirements necessitates higher withstand voltages for these components; and achieving the same voltage and performance would be more expensive. To solve this problem, there is an urgent need to design a constant current system that can meet different voltage levels and its implementation method. Utility Model Content

[0003] Purpose of the utility model: The purpose of this utility model is to provide a high and low voltage constant current source system that can meet different voltage levels.

[0004] Technical Solution: The high and low voltage constant current source system of this utility model includes a high voltage DC battery pack, resistors R1, R2, R3, R4, and R5; diodes D1, D2, D3, D4, D5, D6, and D7; transistors Q1, Q2, and Q3; and bidirectional Zener diodes TV1, TV2, TV3, and TV4. The high voltage DC battery pack is positive at the top and negative at the bottom. The positive terminal is connected to one end of resistor R1, and the other end of resistor R1 is connected to the anode of diode D1 and resistor R2. Diodes D1 and D2 are connected in series and in parallel with resistor R2. The cathode of diode D2 is connected in series with bidirectional Zener diodes TV1, TV2, and TV3 and is connected to the negative terminal of the battery pack.

[0005] Furthermore, the cathode of the diode D2 is connected to one end of the resistor R3 and the base of the transistor Q1, respectively. The resistor R3 is the bias resistor of the transistor Q1, and the other end of the resistor R3 is connected to the collector of the transistor Q1.

[0006] Furthermore, one end of the bidirectional Zener diode TV1 is connected to the cathode of diode D2, and the other end is connected to one end of resistor R4 and the base of transistor Q2, respectively. Resistor R4 is the bias resistor of transistor Q2, and the other end of resistor R4 is connected to the collector of transistor Q2.

[0007] Furthermore, one end of the bidirectional Zener diode TV2 is connected to the bidirectional Zener diode TV1, and the other end is connected to one end of resistor R4 and the base of transistor Q2, respectively. Resistor R4 is the bias resistor of transistor Q2, and the other end of resistor R4 is connected to the collector of transistor Q2.

[0008] Furthermore, one end of the bidirectional Zener diode TV3 is connected to the bidirectional Zener diode TV2, and the other end is connected to one end of resistor R5 and the base of transistor Q3, respectively. Resistor R5 is the bias resistor of transistor Q3, and the other end of resistor R5 is connected to the collector of transistor Q3.

[0009] Furthermore, transistors Q1, Q2, Q3 and diode D7 are connected in series, with one end connected to resistor R1 and the other end connected to the negative terminal of the battery pack. The bases of transistors Q1, Q2 and Q3 are respectively connected to the upper ends of bidirectional Zener diodes TV1, TV2 and TV3 to obtain voltage.

[0010] Furthermore, the two ends of diode D3 are respectively connected to the base and emitter of transistor Q1, and connected to resistor R3; the two ends of diode D4 are respectively connected to the base and emitter of transistor Q2, and connected to resistor R4; the two ends of diode D5 are respectively connected to the base and emitter of transistor Q3, and connected to resistor R5.

[0011] Furthermore, one end of diode D6 is connected to the collector of transistor Q3, and the other end is connected to the negative terminal of the battery pack. Diode D6 and diode D7 are connected in parallel.

[0012] Beneficial effects: Compared with the prior art, this utility model has the following advantages: This utility model can prevent accidental contact caused by the inability of high-voltage energy storage devices to discharge quickly due to power failure and unpredictable discharge time. The withstand voltage meets the requirements of existing vehicle power supplies; the structure is simple, requires fewer types of components, and is inexpensive; it covers a wide voltage range; and it supports reverse connection protection. Attached Figure Description

[0013] Figure 1 This is a structural diagram of the device of this utility model. Detailed Implementation

[0014] The technical solution of this utility model will be further described below with reference to the accompanying drawings.

[0015] like Figure 1As shown, the high and low voltage constant current source system of this utility model includes a high voltage DC battery pack, resistors R1, R2, R3, R4, and R5; diodes D1, D2, D3, D4, D5, D6, and D7; transistors Q1, Q2, and Q3; and bidirectional Zener diodes TV1, TV2, TV3, and TV4. The high voltage DC battery pack is positive at the top and negative at the bottom. The positive terminal is connected to one end of resistor R1, and the other end of resistor R1 is connected to the anode of diode D1 and resistor R2. Diodes D1 and D2 are connected in series and in parallel with resistor R2. The cathode of diode D2 is connected in series with bidirectional Zener diodes TV1, TV2, and TV3 and is connected to the negative terminal of the battery pack.

[0016] The cathode of diode D2 is connected to one end of resistor R3 and the base of transistor Q1, respectively. Resistor R3 is the bias resistor for transistor Q1, and the other end of resistor R3 is connected to the collector of transistor Q1. One end of bidirectional Zener diode TV1 is connected to the cathode of diode D2, and the other end is connected to one end of resistor R4 and the base of transistor Q2, respectively. Resistor R4 is the bias resistor for transistor Q2, and the other end of resistor R4 is connected to the collector of transistor Q2.

[0017] One end of the bidirectional Zener diode TV2 is connected to the bidirectional Zener diode TV1, and the other end is connected to one end of resistor R4 and the base of transistor Q2. Resistor R4 is the bias resistor for transistor Q2, and the other end of resistor R4 is connected to the collector of transistor Q2. One end of the bidirectional Zener diode TV3 is connected to the bidirectional Zener diode TV2, and the other end is connected to one end of resistor R5 and the base of transistor Q3. Resistor R5 is the bias resistor for transistor Q3, and the other end of resistor R5 is connected to the collector of transistor Q3. Transistors Q1, Q2, Q3, and diode D7 are connected in series, one end of which is connected to resistor R1, and the other end is connected to the negative terminal of the battery pack. The bases of transistors Q1, Q2, and Q3 are connected to the upper terminals of bidirectional Zener diodes TV1, TV2, and TV3, respectively, to obtain voltage. Diode D3 is connected to the base and emitter of transistor Q1, and is also connected to resistor R3. Diode D4 is connected to the base and emitter of transistor Q2, and is also connected to resistor R4. Diode D5 is connected to the base and emitter of transistor Q3, and is also connected to resistor R5. Diode D6 is connected to the collector of transistor Q3 at one end and to the negative terminal of the battery pack at the other end. Diodes D6 and D7 are connected in parallel.

[0018] Working principle:

[0019] (1) By limiting the current of resistor R1, diodes D1 and D2 are fixed to a voltage drop of 0.7V. The parallel resistors achieve a voltage of 1.4V across resistor R2, so that the current flowing through resistor R2 is F1.4V / R2. Based on the large current, the resistance value of resistor R2 and the number of diodes are determined.

[0020] (2) Transistors Q1, Q2, and Q3 are PNP transistors. When the battery is connected, the current first flows through resistors R1, R2, Q1, and R3, then through Q2 and R4, and finally through Q3, R5, and diode D7, causing Q1, Q2, and Q3 to conduct, thus making the transistors emit light.

[0021] (3) Resistors R3, R4 and R5 are selected with large resistance values. The transistor is in the amplification region and the minimum withstand voltage of the transistor is set to be greater than 350V.

[0022] The battery pack's rated voltage range is 0-1200V; R1 mainly prevents excessive breakdown current from the Zener diode, which could cause overheating and damage the Zener diode. Its resistance value and package size can be adjusted based on the brightness of diode D7 and the battery pack voltage; resistor R2 limits the current flowing through diode D7. (If diode D7 requires 2mA, then the resistance of R2 is approximately 390Ω (VFD1+VFD2) / R2, and the voltage drop between VFD1 and VFD2 is generally 0.7V).

[0023] The voltage regulation threshold of bidirectional Zener diodes TV1, TV2, and TV3 can be determined based on the highest voltage of the battery pack. (For example, if the highest voltage is 1200V, transistors Q1, Q2, and Q3 are required. Each transistor has a withstand voltage of 400V across its CE terminals. Therefore, the breakdown threshold of bidirectional Zener diodes TV1, TV2, and TV3 must not exceed 400V to prevent the battery pack voltage from being too high, which could cause the CE pins of transistors Q1, Q2, and Q3 to exceed their withstand voltage and be damaged.)

[0024] Meanwhile, bidirectional Zener diodes TV1, TV2, and TV3 also provide turn-on voltage for transistors Q1, Q2, and Q3 (transistors Q1, Q2, and Q3 are PNP transistors, and the conduction condition is Vb < Ve).

[0025] Resistors R3, R4, and R5 serve a protective function. Furthermore, resistors R3, R4, and R5 should be selected in the megohm range to ensure that the transistor is not fully conducting. Diodes D3, D4, D5, and D6 prevent the battery from being packaged upside down. The transistor's Vcb withstand voltage is broken down. The voltage is clamped by the voltage divider formed by the diodes and resistors R3, R4, and R5.

[0026] Diode D7 is a light-emitting diode, typically with a voltage drop of around 3V and a current of 2mA.

Claims

1. A high-low constant current source system, characterized by, The high-voltage direct-current battery pack, resistors R1, R2, R3, R4, R5, diodes D1, D2, D3, D4, D5, D6, D7, transistors Q1, Q2, Q3, and bidirectional voltage stabilizers TV1, TV2, TV3, and TV4 are included.

2. The high-low voltage constant current source system of claim 1, wherein, The cathode of the diode D2 is connected to one end of the resistor R3 and the base of the transistor Q1, and the resistor R3 is the bias resistor of the transistor Q1.

3. The high-low voltage constant current source system of claim 1, wherein, One end of the bidirectional voltage stabilizer TV1 is connected to the cathode of the diode D2, and the other end is connected to one end of the resistor R4 and the base of the transistor Q2, and the resistor R4 is the bias resistor of the transistor Q2.

4. The high-low voltage constant current source system of claim 1, wherein, One end of the bidirectional voltage stabilizer TV2 is connected to the bidirectional voltage stabilizer TV1, and the other end is connected to one end of the resistor R4 and the base of the transistor Q2, and the resistor R4 is the bias resistor of the transistor Q2.

5. The high-low voltage constant current source system of claim 1, wherein, One end of the bidirectional voltage stabilizer TV3 is connected to the bidirectional voltage stabilizer TV2, and the other end is connected to one end of the resistor R5 and the base of the transistor Q3, and the resistor R5 is the bias resistor of the transistor Q3.

6. The high-low voltage constant current source system of claim 1, wherein, The transistors Q1, Q2, Q3, and diode D7 are connected in series, one end is connected to the resistor R1, and the other end is connected to the negative electrode of the battery pack, and the bases of the transistors Q1, Q2, Q3 are connected to the upper end of the bidirectional voltage stabilizers TV1, TV2, and TV3, respectively.

7. The high-low voltage constant current source system of claim 1, wherein, The two ends of the diode D3 are connected to the base and emitter of the transistor Q1, and are connected to the resistor R3; the two ends of the diode D4 are connected to the base and emitter of the transistor Q2, and are connected to the resistor R4; the two ends of the diode D5 are connected to the base and emitter of the transistor Q3, and are connected to the resistor R5.

8. The high-low voltage constant current source system of claim 1, wherein, One end of the diode D6 is connected to the collector of the transistor Q3, and the other end is connected to the negative electrode of the battery pack, and the diode D6 and diode D7 are connected in parallel.

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