Constant-current discharge device and power supply with constant-current discharge device

Abstract

The constant-current discharging device comprises a discharging voltage detecting circuit, a reference voltage adjusting circuit, a constant-current driving circuit and a constant-current circuit. The discharge voltage detection circuit is connected between the positive electrode and the negative electrode of the direct-current voltage and is used for receiving the direct-current voltage. The reference voltage adjusting circuit is connected with the discharge voltage detecting circuit, and the reference voltage adjusting circuit provides the power supply voltage and determines the magnitude of the discharge current. The constant current driving circuit is connected with the discharge voltage detecting circuit and the reference voltage adjusting circuit and is used for providing driving voltage. The constant-current circuit is connected with the reference voltage adjusting circuit and the constant-current driving circuit, and the constant-current circuit is powered by the power supply voltage and driven by the driving voltage. When the direct current voltage is smaller than the voltage threshold value, the constant-current circuit conducts constant-current discharging according to the magnitude of the discharging current.

Description

Technical Field

[0001] The present invention relates to a discharge device and a power supply having a discharge device, particularly to a constant current discharge device and a power supply having a constant current discharge device. Background Art

[0002] At present, due to the pursuit of high efficiency and energy conservation in power supplies, the power loss of the power supply itself is getting smaller and smaller. When the power supply is turned off (AC OFF), there will be a residual voltage on the capacitor. This residual high voltage takes a long time (for example, dozens of minutes) to be consumed below the safe voltage. Therefore, during this discharge time, it may cause electric shock and electrocution risks when personnel (such as maintenance personnel, system operators, etc.) touch it, and it may also cause component damage.

[0003] Therefore, how to design a constant current discharge device and a power supply having a constant current discharge device to solve the problems and technical bottlenecks existing in the prior art is an important issue studied by the inventors of the present invention. Summary of the Invention

[0004] The purpose of the present invention is to provide a constant current discharge device to solve the problems existing in the prior art.

[0005] To achieve the above object, the constant current discharge device proposed by the present invention includes a discharge voltage detection circuit, a reference voltage adjustment circuit, a constant current drive circuit, and a constant current circuit; the discharge voltage detection circuit is connected between the positive and negative poles of the DC voltage to receive the DC voltage; the reference voltage adjustment circuit is connected to the discharge voltage detection circuit, and the reference voltage adjustment circuit is used to provide a supply voltage and determine the magnitude of the discharge current; the constant current drive circuit is connected to the discharge voltage detection circuit and the reference voltage adjustment circuit, and the constant current drive circuit is used to provide a drive voltage; the constant current circuit is connected to the reference voltage adjustment circuit and the constant current drive circuit, the constant current circuit is powered by the supply voltage and driven by the drive voltage; when the DC voltage is less than the voltage threshold, the constant current circuit performs constant current discharge according to the magnitude of the discharge current.

[0006] In an embodiment, when the DC voltage is greater than or equal to the voltage threshold, the constant current circuit prohibits constant current discharge.

[0007] In an embodiment, the discharge voltage detection circuit includes a voltage stabilization unit, a voltage division unit, and a first switch; the voltage stabilization unit receives the DC voltage and provides a stabilized voltage; the voltage division unit is connected to the voltage stabilization unit to receive the stabilized voltage and divide the stabilized voltage to provide a divided voltage; the first switch is connected to the voltage division unit and receives the divided voltage to control the on and off of the first switch.

[0008] In one embodiment, the discharge voltage detection circuit further includes a first protection unit; the first protection unit is connected to the voltage dividing unit and receives the divided voltage, and is used to stabilize the divided voltage to protect the first switch.

[0009] In one embodiment, the reference voltage adjustment circuit includes a first resistor loop; the first resistor loop includes at least one resistor, which is connected between the discharge voltage detection circuit and the constant current circuit, and is used to receive the DC voltage, adjust the magnitude of the supply voltage, and determine the magnitude of the discharge current.

[0010] In one embodiment, the constant current driving circuit includes a second resistor loop; the second resistor loop includes at least one resistor, and is used to provide the driving voltage for driving the constant current circuit.

[0011] In one embodiment, the constant current driving circuit further includes a second protection unit; the second protection unit is connected to the second resistor loop and is used to protect the constant current circuit.

[0012] In one embodiment, the constant current circuit includes a second switch and a third switch; the second switch is connected to the reference voltage adjustment circuit and receives the supply voltage; the third switch is connected to the second switch; when the second switch is turned on, the third switch provides a discharge path for the discharge current to flow through the discharge path for constant current discharge.

[0013] Another object of the present invention is to provide a power supply to solve the problems existing in the prior art.

[0014] To achieve the foregoing object, the power supply proposed by the present invention receives an AC input voltage and converts the AC input voltage to provide a DC output voltage; the power supply includes an AC side circuit, a DC bus, a bus capacitor, a DC side circuit, and a constant current discharge device; the AC side circuit receives the AC input voltage and is used to convert the AC input voltage into a DC voltage; the DC bus is connected to the output side of the AC side circuit. The bus capacitor is connected to the DC bus and is used to establish a DC voltage on the DC bus; the DC side circuit is connected to the DC bus and is used to convert the DC voltage into a DC output voltage; the constant current discharge device is connected in parallel between the bus capacitor and the input side of the DC side circuit and is used to receive the DC voltage; when the DC voltage is less than the voltage threshold, the constant current discharge device is used to perform constant current discharge on the energy stored in the bus capacitor.

[0015] In one embodiment, the constant current discharging device includes a discharging voltage detection circuit, a reference voltage adjustment circuit, a constant current driving circuit, and a constant current circuit. The discharging voltage detection circuit is connected between the positive and negative electrodes of the DC voltage to receive the DC voltage. The reference voltage adjustment circuit is connected to the discharging voltage detection circuit, provides a supply voltage, and determines the magnitude of the discharging current. The constant current driving circuit is connected to the discharging voltage detection circuit and the reference voltage adjustment circuit to provide a driving voltage. The constant current circuit is connected to the reference voltage adjustment circuit and the constant current driving circuit, is powered by the supply voltage, and is driven by the driving voltage. When the DC voltage is less than the voltage threshold, the constant current circuit performs constant current discharging according to the magnitude of the discharging current.

[0016] In one embodiment, when the DC voltage is greater than or equal to the voltage threshold, the constant current circuit prohibits constant current discharging.

[0017] In one embodiment, the discharging voltage detection circuit includes a voltage stabilizing unit, a voltage dividing unit, and a first switch. The voltage stabilizing unit receives the DC voltage and provides a stabilized voltage. The voltage dividing unit is connected to the voltage stabilizing unit to receive the stabilized voltage and divide the stabilized voltage to provide a divided voltage. The first switch is connected to the voltage dividing unit and receives the divided voltage to control the conduction and cut-off of the first switch.

[0018] In one embodiment, the discharging voltage detection circuit further includes a first protection unit. The first protection unit is connected to the voltage dividing unit and receives the divided voltage to stabilize the divided voltage to protect the first switch.

[0019] In one embodiment, the reference voltage adjustment circuit includes a first resistor circuit. The first resistor circuit includes at least one resistor, is connected between the discharging voltage detection circuit and the constant current circuit, receives the DC voltage, adjusts the magnitude of the supply voltage, and determines the magnitude of the discharging current.

[0020] In one embodiment, the constant current driving circuit includes a second resistor circuit. The second resistor circuit includes at least one resistor to provide a driving voltage for driving the constant current circuit.

[0021] In one embodiment, the constant current driving circuit further includes a second protection unit. The second protection unit is connected to the second resistor circuit to protect the constant current circuit.

[0022] In one embodiment, the constant current circuit includes a second switch and a third switch. The second switch is connected to the reference voltage adjustment circuit and receives the supply voltage. The third switch is connected to the second switch. When the second switch is turned on, the third switch provides a discharging path for the discharging current to flow through the discharging path for constant current discharging.

[0023] In one embodiment, the AC side circuit includes an electromagnetic interference filtering circuit, an input rectifying and filtering circuit, and a power factor correction conversion circuit; the electromagnetic interference filtering circuit receives an AC input voltage and converts the AC input voltage into a filtered voltage; the input rectifying and filtering circuit is connected to the electromagnetic interference filtering circuit, receives the filtered voltage, and converts the filtered voltage into a rectified and filtered voltage; the power factor correction conversion circuit is connected to the input rectifying and filtering circuit and converts the rectified and filtered voltage into a DC voltage.

[0024] In one embodiment, the DC side circuit includes a DC-DC conversion circuit and an output rectifying and filtering circuit; the DC-DC conversion circuit receives the DC voltage and converts the DC voltage into a converted voltage; the output rectifying and filtering circuit is connected to the DC-DC conversion circuit and converts the converted voltage into a DC output voltage.

[0025] Thus, the constant current discharge device and the power supply proposed by the present invention have the following features and advantages:

[0026] 1. The constant current discharge device of the present invention can be applied to various power supplies for discharging the capacitance energy storage.

[0027] 2. The constant current discharge device can be arranged on an independent circuit board to form a modular design, and then connected in parallel to the DC bus of the power supply to provide constant current discharge.

[0028] 3. The active constant current discharge realized by controlling the transistor (power) switch, and the magnitude of the discharge current can be designed according to practical requirements.

[0029] 4. By discharging the residual voltage on the capacitor, the risk of electric shock and electrocution to maintenance personnel or system operators is avoided, and component damage is also avoided.

[0030] 5. Compared with the traditional method that requires a long time (such as nearly half an hour) to release the residual high voltage, the active constant current discharge designed by the present invention can achieve complete energy release in a very short time (such as within 3 minutes).

[0031] 6. Through the active constant current discharge of the present invention, the advantages of low loss (i.e., high efficiency) and high energy saving of the power supply can be realized.

[0032] In order to further understand the technologies, means and effects adopted by the present invention to achieve the predetermined purpose, please refer to the following detailed description and drawings of the present invention. It is believed that the purpose, features and characteristics of the present invention can be deeply and specifically understood therefrom. However, the attached drawings are only for reference and illustration, and are not used to limit the present invention. Description of the Drawings

[0033] Figure 1 It is a circuit module diagram of the constant current discharge device of the present invention.

[0034] Figure 2 This is the circuit diagram of the constant current discharge device of the present invention.

[0035] Figure 3 This is the waveform diagram showing the control of the constant current discharge device of the present invention according to the DC voltage.

[0036] Figure 4 This is the circuit module diagram of the power supply with the constant current discharge device of the present invention.

[0037] Description of Reference Numerals

[0038] 10 Constant current discharge device

[0039] 11 Discharge voltage detection circuit

[0040] 12 Reference voltage adjustment circuit

[0041] 13 Constant current drive circuit

[0042] 14 Constant current circuit

[0043] 111 Voltage stabilizing unit

[0044] 112 Voltage dividing unit

[0045] 113 First switch

[0046] 114 First protection unit

[0047] 121 First resistor circuit

[0048] 131 Second resistor circuit

[0049] 132 Second protection unit

[0050] 141 Second switch

[0051] 142 Third switch

[0052] 100 Power supply

[0053] 110 AC side circuit

[0054] 120 DC side circuit

[0055] 110-1 Electromagnetic interference filtering circuit

[0056] 110-2 Input rectifier filtering circuit

[0057] 110-3 Power factor correction conversion circuit

[0058] 120-1 DC-DC conversion circuit

[0059] 120-2 Output rectifier filtering circuit

[0060] Vbulk DC voltage

[0061] V+ Positive electrode

[0062] V- Negative electrode

[0063] Vs Supply voltage

[0064] Vr Drive voltage

[0065] Vth Voltage threshold

[0066] Vz Zener voltage

[0067] Vd Dividing voltage

[0068] Vin AC input voltage

[0069] Vout DC output voltage

[0070] Vef Filtering voltage

[0071] Vrf Rectifying and filtering voltage

[0072] Vcr Conversion voltage

[0073] Cbulk Bus capacitor

[0074] EZD11 - EZD14 Zener diode

[0075] ER10 First voltage - dividing resistor

[0076] ER11 Second voltage - dividing resistor

[0077] ER12, ER13 Resistors

[0078] ER16, ER17 Resistors

[0079] DC_BUS DC bus Detailed implementation manners

[0080] Regarding the technical content and detailed description of the present invention, it is described in detail below in conjunction with the accompanying drawings.

[0081] Please refer to Figure 1 as shown. It is a circuit module diagram of the constant - current discharging device of the present invention. The constant - current discharging device 10 includes a discharging voltage detection circuit 11, a reference voltage adjustment circuit 12, a constant - current driving circuit 13, and a constant - current circuit 14.

[0082] The discharging voltage detection circuit 11 is connected between the positive electrode V+ and the negative electrode V - of the DC voltage Vbulk for receiving the DC voltage Vbulk. Wherein the DC voltage Vbulk is established on a capacitor( Figure 1The DC voltage on (not shown). The reference voltage adjustment circuit 12 is connected to the discharge voltage detection circuit 11. The reference voltage adjustment circuit 12 is used to provide the supply voltage Vs and determine the magnitude of the discharge current.

[0083] The constant current drive circuit 13 is connected to the discharge voltage detection circuit 11 and the reference voltage adjustment circuit 12. The constant current drive circuit 13 is used to provide the drive voltage Vr. The constant current circuit 14 is connected to the reference voltage adjustment circuit 12 and the constant current drive circuit 13. The constant current circuit 14 is powered by the supply voltage Vs and driven by the drive voltage Vr.

[0084] Thereby, when the DC voltage Vbulk is less than the voltage threshold Vth, the constant current circuit 14 performs constant current discharge according to the magnitude of the discharge current. Conversely, when the DC voltage Vbulk is greater than or equal to the voltage threshold Vth, the constant current circuit 14 prohibits constant current discharge. Incidentally, the judgment that the aforementioned DC voltage Vbulk is less than the voltage threshold Vth, or greater than or equal to the voltage threshold Vth does not limit the present invention. That is, the judgment that the DC voltage Vbulk is greater than the voltage threshold Vth, or less than or equal to the voltage threshold Vth can also achieve constant current discharge of the constant current circuit 14 and prohibition of constant current discharge of the constant current circuit 14.

[0085] Please refer to Figure 2 shown, which is the circuit diagram of the constant current discharge device of the present invention. Hereinafter, each circuit of the constant current discharge device 10 will be described. As Figure 2 shown, the discharge voltage detection circuit 11 includes a voltage stabilizing unit 111, a voltage dividing unit 112, and a first switch 113 (i.e., Figure 2 EQ10 in). The voltage stabilizing unit 111 receives the DC voltage Vbulk and provides a stabilized voltage Vz. In an embodiment, the voltage stabilizing unit 111 includes a plurality of serially connected Zener diodes. As Figure 2 shown, the voltage stabilizing unit 111 includes 4 Zener diodes, namely Zener diode EZD11 - Zener diode EZD14. The reverse breakdown voltage of each Zener diode is assumed to be 75 volts (the present invention is not limited by this value). Therefore, when the serially connected Zener diodes break down (Zener breakdown) under the reverse voltage, a stable voltage of 300 volts can be provided.

[0086] The voltage dividing unit 112 is connected to the voltage stabilizing unit 111 to receive the stabilized voltage Vz and divide the stabilized voltage Vz to provide a divided voltage Vd. Specifically, the voltage dividing unit 112 includes a first voltage dividing resistor ER10 and a second voltage dividing resistor ER11. That is, the stabilized voltage Vz is divided according to the resistance ratio relationship between the first voltage dividing resistor ER10 and the second voltage dividing resistor ER11 to generate a divided voltage Vd across the second voltage dividing resistor ER11, that is, Vd = Vz * (ER11 / (ER10 + ER11)), where Vz is the stabilized voltage, ER10 is the resistance value of the first voltage dividing resistor, and ER11 is the resistance value of the second voltage dividing resistor.

[0087] The first switch 113 (EQ10) is connected to the voltage dividing unit 112 and receives the divided voltage Vd to control the conduction and cutoff of the first switch 113 (EQ10). In addition, the discharge voltage detection circuit 11 further includes a first protection unit 114. The first protection unit 114 preferably uses a zener diode EZD15. The first protection unit 114 is connected to the voltage dividing unit 112 and receives the divided voltage Vd to stabilize the divided voltage Vd to protect the first switch 113 (EQ10). As for the detailed operation and action principle of the discharge voltage detection circuit 11, it will be described in detail later.

[0088] As Figure 2 shown, the reference voltage adjustment circuit 12 includes a first resistor circuit 121. The first resistor circuit 121 includes at least one resistor. Figure 2 In this case, the first resistor circuit 121 uses a series-connected resistor ER16 and resistor ER17. The first resistor circuit 121 is connected between the discharge voltage detection circuit 11 and the constant current circuit 14 to receive the DC voltage Vbulk, adjust the magnitude of the supply voltage Vs, and determine the magnitude of the discharge current. As for the detailed operation and action principle of the reference voltage adjustment circuit 12, it will be described in detail later.

[0089] As Figure 2 shown, the constant current driving circuit 13 includes a second resistor circuit 131. The second resistor circuit 131 includes at least one resistor. Figure 2 In this case, the first resistor circuit 121 uses a series-connected resistor ER12 and resistor ER13 to provide a driving voltage Vr for driving the constant current circuit 14. In addition, the constant current driving circuit 13 further includes a second protection unit 132. The second protection unit 132 preferably uses a zener diode EZD16. The second protection unit 132 is connected to the second resistor circuit 131 to protect the constant current circuit 14. As for the detailed operation and action principle of the constant current driving circuit 13, it will be described in detail later.

[0090] As Figure 2 shown, the constant current circuit 14 includes a second switch 141 (i.e., Figure 2in EQ11) and the third switch 142 (i.e., Figure 2 in EQ12). The second switch 141 (EQ11) is connected to the reference voltage adjustment circuit 12 and receives the supply voltage Vs. The third switch 142 is connected to the second switch 141 (EQ11). When the second switch 141 (EQ11) is turned on, the third switch 142 (EQ12) provides a discharge path for the discharge current to flow through the discharge path for constant current discharge. As for the detailed operation and action principle of the constant current circuit 14, it will be described in detail later.

[0091] Next, with reference to Figure 3 and the assumed data, the detailed operation and action principle of the discharge voltage detection circuit 11, the reference voltage adjustment circuit 12, the constant current drive circuit 13, and the constant current circuit 14 will be described.

[0092] Please refer to Figure 3 as shown, which is a waveform diagram of the constant current discharge device of the present invention controlled according to the DC voltage. Assume that under normal operation, for example, when the input power supply of the power supply is normally powered, the DC voltage Vbulk is about 400 volts, and the set voltage threshold Vth is 300 volts (an ideal state for easy explanation) or 310 volts (the actual state considering component characteristics). During the period from time t0 to time t1, the input power supply of the power supply is normally powered. Although the DC voltage Vbulk may have a voltage drop (about 10 volts) due to the load condition or the input power supply condition, such a voltage drop is a phenomenon that occurs during the normal operation process. Therefore, in this case, the DC voltage Vbulk will not be less than (lower than) the voltage threshold Vth, so the constant current circuit 14 prohibits constant current discharge, that is, the constant current discharge operation of the constant current circuit 14 is not started.

[0093] With reference to Figure 2 and Figure 3, during the period from time t0 to time t1, that is, the input power supply of the power supply is normally powered, so the DC voltage Vbulk is about 400 volts. Since the voltage stabilizing unit 111 includes 4 voltage stabilizing diodes, namely voltage stabilizing diodes EZD11 - EZD14, and the reverse breakdown voltage of each voltage stabilizing diode is assumed to be 75 volts, the breakdown of the series-connected voltage stabilizing diodes by the DC voltage Vbulk under the action of the reverse voltage enables the voltage stabilizing unit 111 to provide a stable voltage of 300 volts. That is, the voltage stabilizing unit 111 provides a regulated voltage Vz of 300 volts. Therefore, the voltage dividing unit 112, through the resistance design of the first voltage dividing resistor ER10 and the second voltage dividing resistor ER11, makes the divided voltage Vd obtained after dividing the regulated voltage Vz be about 15 volts. Such a 15-volt divided voltage Vd will cause the first switch 113 (EQ10) to conduct. In this embodiment, the first switch 113 (EQ10) is an n-type MOSFET transistor switch, but the present invention is not limited thereto.

[0094] In addition, the reverse breakdown voltage of the first protection unit 114 (EZD15) can be designed to be 15 volts. Therefore, once the divided voltage Vd after being divided by the voltage dividing unit 112 exceeds 15 volts, it will cause the first protection unit 114 (EZD15) to provide a stable voltage of 15 volts to prevent an excessive voltage from driving the first switch 113 (EQ10) and damaging the first switch 113 (EQ10), thereby protecting the first switch 113 (EQ10).

[0095] Once the first switch 113 (EQ10) conducts, the drain voltage of the first switch 113 (EQ10) is 0 volts grounded. Therefore, this voltage is provided to the gate of the second switch 141 (EQ11) of the constant current circuit 14, which will cause the second switch 141 (EQ11) to turn off. In other words, the driving voltage Vr for driving the constant current circuit 14 provided by the constant current driving circuit 13 is 0 volts, so the constant current circuit 14 cannot be driven to operate. In this embodiment, the second switch 141 (EQ11) is an n-type MOSFET transistor switch, but the present invention is not limited thereto. Once the second switch 141 (EQ11) turns off, it will cause the constant current circuit 14 to prohibit constant current discharge, that is, the constant current discharge operation of the constant current circuit 14 is not started.

[0096] Refer to in conjunction with Figure 2 and Figure 3, after time t1, assuming that the power supply is turned off, or there is a power outage or continuous abnormal power supply in the input power supply of the power supply, the DC voltage Vbulk gradually decreases from about 400 volts. Until time t2, the DC voltage Vbulk is less than the voltage threshold Vth (i.e., 300 volts), so the constant current circuit 14 performs constant current discharge, that is, starts the constant current discharge operation of the constant current circuit 14, so that the constant current circuit 14 performs constant current discharge according to the magnitude of the discharge current.

[0097] When the DC voltage Vbulk is less than 300 volts, since the DC voltage Vbulk cannot cause the series-connected zener diodes to break down under the reverse voltage, the zener voltage Vz at this time will only be the sum of the forward voltages of the four zener diodes, that is, zener diode EZD11 - zener diode EZD14, which is about 2.8 volts. Therefore, after the voltage divider unit 112 divides the 2.8-volt zener voltage Vz again, the obtained divided voltage Vd will not be sufficient to drive the first switch 113 (EQ10) to conduct.

[0098] Once the first switch 113 (EQ10) is turned off, the driving voltage Vr provided by the constant current driving circuit 13 to drive the constant current circuit 14 is no longer 0 volts, but is sufficient to drive the second switch 141 (EQ11) to conduct. It is worth mentioning that when the first switch 113 (EQ10) is turned off, the hundreds of volts of voltage of the DC voltage Vbulk will be provided to the gate of the second switch 141 (EQ11) of the constant current circuit 14 through the second resistor circuit 131 of the constant current driving circuit 13. However, since the constant current driving circuit 13 has a second protection unit 132 (EZD16), the reverse breakdown voltage of the second protection unit 132 (EZD16) can be designed to be 15 volts, so that the second protection unit 132 (EZD16) provides a stable voltage of 15 volts as the gate voltage to drive the second switch 141 (EQ11) to conduct. Therefore, once the second switch 141 (EQ11) conducts, and then controls the third switch 142 (EQ12) to conduct, it will cause the constant current circuit 14 to perform constant current discharge, that is, start the constant current discharge operation of the constant current circuit 14, so that the constant current circuit 14 discharges at a constant current according to the magnitude of the discharge current through the discharge path provided by the third switch 142 (EQ12). Therefore, the constant current discharge operation disclosed in the present invention is an active constant current discharge realized by controlling a transistor (power) switch.

[0099] It is worth mentioning that at least one resistor included in the first resistor circuit 121 of the reference voltage adjustment circuit 12, namely resistor ER16 and resistor ER17, is used to determine the magnitude of the discharge current of the constant current circuit 14. Specifically, since the second switch 141 (EQ11) conducts to enable the constant current circuit 14 to perform constant current discharge, the magnitude of the discharge current (Idis) is approximately the direct current voltage Vbulk minus the collector-emitter voltage (VCE,EQ12) of the third switch 142 (EQ12), and then divided by the resistance value of the first resistor circuit 121, that is, Idis = (Vbulk - VCE,EQ12) / (ER16 + ER17). Therefore, the magnitude of the discharge current of the constant current circuit 14 can be determined by designing the resistance values of at least one resistor (such as resistor ER16 and resistor ER17) of the first resistor circuit 121. That is, when the resistance value of the first resistor circuit 12 is larger, the discharge current is smaller; conversely, when the resistance value is smaller, the discharge current is larger. For example, if the total resistance value of resistor ER16 and resistor ER17 in the first resistor circuit 12 is 300 kΩ, the discharge current is approximately 1 mA. Incidentally, in one embodiment, the withstand voltage of resistor ER16 and resistor ER17 can be 200 V, but the present invention is not limited thereto.

[0100] Please refer to Figure 4 As shown, it is a circuit module diagram of a power supply with a constant current discharge device according to the present invention. The power supply 100 receives an AC input voltage Vin and converts the AC input voltage Vin to provide a DC output voltage Vout. The power supply 100 includes an AC side circuit 110, a DC bus DC_BUS, a bus capacitor Cbulk, a DC side circuit 120, and a constant current discharge device 10.

[0101] The AC side circuit 110 receives the AC input voltage Vin and is used to convert the AC input voltage Vin into a DC voltage Vbulk. The AC side circuit 110 includes an electromagnetic interference filtering circuit 110-1, an input rectifying and filtering circuit 110-2, and a power factor correction conversion circuit 110-3. The electromagnetic interference filtering circuit 110-1 receives the AC input voltage Vin and converts the AC input voltage Vin into a filtered voltage Vef. The input rectifying and filtering circuit 110-2 is connected to the electromagnetic interference filtering circuit 110-1, receives the filtered voltage Vef, and converts the filtered voltage Vef into a rectified and filtered voltage Vrf. The power factor correction conversion circuit 110-3 is connected to the input rectifying and filtering circuit 110-2 and converts the rectified and filtered voltage Vrf into a DC voltage Vbulk.

[0102] The DC bus (DC_BUS) is connected to the output side of the AC-side circuit 110. The bus capacitor Cbulk is connected to the DC bus (DC_BUS) to establish a DC voltage Vbulk on the DC bus (DC_BUS). The constant-current discharge device 10 is connected in parallel between the bus capacitor Cbulk and the input side of the DC-side circuit 120 to receive the DC voltage Vbulk. The DC-side circuit 120 includes a DC-DC conversion circuit 120-1 and an output rectification and filtering circuit 120-2. The DC-DC conversion circuit 120-1 receives the DC voltage Vbulk and converts the DC voltage Vbulk into a converted voltage Vcr. The output rectification and filtering circuit 120-2 is connected to the DC-DC conversion circuit 120-1 and converts the converted voltage Vcr into a DC output voltage Vout.

[0103] When the DC voltage Vbulk is less than the voltage threshold Vth, the constant-current discharge device 10 is used to perform a constant-current discharge of the energy stored in the bus capacitor Cbulk. Referring again to Figure 1 、 Figure 2 and Figure 3 , when the power supply 100 is shut down, or the input power of the power supply 100 is cut off or there is continuous abnormal power supply, the DC voltage Vbulk gradually decreases from about 400 volts. Until the DC voltage Vbulk is less than the voltage threshold Vth (i.e., 300 volts), the constant-current circuit 14 performs a constant-current discharge, that is, the constant-current discharge operation of the constant-current circuit 14 is started, so that the constant-current circuit 14 performs a constant-current discharge according to the magnitude of the discharge current, thereby performing a constant-current discharge of the energy stored in the bus capacitor Cbulk. Among them, the DC voltage Vbulk mentioned in this embodiment is a high voltage (about 400 volts), but it is not limited to a high voltage and can also be a low voltage, that is, the constant-current discharge device 10 of the present invention can be applied to the DC voltage Vbulk of high voltage and low voltage. For the detailed operation of the constant-current discharge device 10 of the power supply 100, reference can be made to the foregoing description and will not be elaborated herein.

[0104] Thereby, the power supply of the present invention having a constant-current discharge device can reduce the discharge time of the bus capacitor Cbulk to less than 3 minutes compared with the power supply of the same specification in the prior art. And the constant-current discharge device uses its active constant-current discharge to make the no-load loss also meet the specification requirements (<0.5W) without affecting the conversion efficiency of the power supply itself.

[0105] In summary, the present invention has the following features and advantages:

[0106] 1. The constant-current discharge device of the present invention can be applied to various power supplies for discharging the energy stored in the capacitor.

[0107] 2. The constant current discharge device can be arranged on an independent circuit board to form a modular design, and then be connected in parallel to the DC bus of the power supply to provide constant current discharge.

[0108] 3. Active constant current discharge is achieved through controlling the transistor (power) switch, and the magnitude of the discharge current can be designed according to practical requirements.

[0109] 4. By discharging the residual voltage on the capacitor, the risk of electric shock and electrocution to maintenance personnel or system operators can be avoided, and component damage can also be avoided.

[0110] 5. Compared with the traditional method that requires a long time (such as nearly half an hour) to release the residual high voltage, the active constant current discharge designed by the present invention can achieve complete energy release in a very short time (such as within 3 minutes).

[0111] 6. Through the active constant current discharge of the present invention, the advantages of low loss (i.e., high efficiency) and high energy saving of the power supply can be achieved.

Claims

1. A constant current discharging device, characterized in that, Comprising: A discharge voltage detection circuit, connected between the positive and negative poles of a DC voltage, for receiving the DC voltage; A reference voltage adjustment circuit, connected to the discharge voltage detection circuit, the reference voltage adjustment circuit providing a supply voltage and determining the magnitude of the discharge current; A constant current drive circuit, connected to the discharge voltage detection circuit and the reference voltage adjustment circuit, the constant current drive circuit providing a drive voltage; And, A constant current circuit, connected to the reference voltage adjustment circuit and the constant current drive circuit, the constant current circuit being powered by the supply voltage and driven by the drive voltage; When the DC voltage is less than the voltage threshold, the constant current circuit performs constant current discharge according to the magnitude of the discharge current.

2. The constant current discharge device according to claim 1, wherein When the DC voltage is greater than or equal to the voltage threshold, the constant current circuit prohibits constant current discharge.

3. The constant current discharge device according to claim 1, characterized in that, The discharge voltage detection circuit includes: A voltage stabilization unit, receiving the DC voltage and providing a stabilized voltage; A voltage division unit, connected to the voltage stabilization unit, receiving the stabilized voltage and dividing the stabilized voltage to provide a divided voltage; and, A first switch, connected to the voltage division unit and receiving the divided voltage, the divided voltage controlling the conduction and cut-off of the first switch.

4. The constant current discharging device according to claim 3, wherein The discharge voltage detection circuit further includes: A first protection unit, connected to the voltage division unit and receiving the divided voltage, stabilizing the divided voltage to protect the first switch.

5. The constant current discharge device according to claim 1, characterized in that The reference voltage adjustment circuit includes: A first resistor circuit, the first resistor circuit including at least one resistor, connected between the discharge voltage detection circuit and the constant current circuit, receiving the DC voltage, adjusting the magnitude of the supply voltage and determining the magnitude of the discharge current.

6. The constant current discharge device according to claim 1, wherein, The constant current drive circuit includes: A second resistor circuit, the second resistor circuit including at least one resistor, providing the drive voltage for driving the constant current circuit.

7. The constant current discharge device according to claim 6, wherein The constant current drive circuit further includes: A second protection unit, connected to the second resistor circuit, protecting the constant current circuit.

8. The constant current discharge device according to claim 1, wherein, The constant current circuit includes: A second switch, connected to the reference voltage adjustment circuit and receiving the supply voltage; and, A third switch, connected to the second switch; When the second switch is conducting, the third switch provides a discharge path for the discharge current to flow through the discharge path for constant current discharge.

9. A power supply, characterized in that, The power supply receives an AC input voltage and converts the AC input voltage to provide a DC output voltage, the power supply including: An AC side circuit, receiving the AC input voltage and converting the AC input voltage to a DC voltage; A DC bus, connected to the output side of the AC side circuit; A bus capacitor, connected to the DC bus, establishing the DC voltage on the DC bus; A DC side circuit, connected to the DC bus, converting the DC voltage to the DC output voltage; and, A constant current discharge device, connected in parallel between the bus capacitor and the input side of the DC side circuit, receiving the DC voltage; When the DC voltage is less than the voltage threshold, the constant current discharge device performs constant current discharge on the energy stored in the bus capacitor.

10. The power supply according to claim 9, characterized in that, The constant current discharge device includes: A discharge voltage detection circuit is connected between the positive and negative poles of a DC voltage and receives the DC voltage; A reference voltage adjustment circuit is connected to the discharge voltage detection circuit. The reference voltage adjustment circuit provides a supply voltage and determines the magnitude of the discharge current; A constant current drive circuit is connected to the discharge voltage detection circuit and the reference voltage adjustment circuit. The constant current drive circuit provides a drive voltage; and A constant current circuit is connected to the reference voltage adjustment circuit and the constant current drive circuit. The constant current circuit is powered by the supply voltage and is driven by the drive voltage; When the DC voltage is less than the voltage threshold, the constant current circuit performs constant current discharge according to the magnitude of the discharge current.

11. The power supply according to claim 10, wherein, When the DC voltage is greater than or equal to the voltage threshold, the constant current circuit prohibits constant current discharge.

12. The power supply according to claim 10, characterized in that, The discharge voltage detection circuit includes: A voltage stabilization unit that receives the DC voltage and provides a stabilized voltage; A voltage dividing unit is connected to the voltage stabilization unit, receives the stabilized voltage, and divides the stabilized voltage to provide a divided voltage; and, A first switch is connected to the voltage dividing unit and receives the divided voltage. The divided voltage controls the conduction and cutoff of the first switch.

13. The power supply according to claim 12, wherein, The discharge voltage detection circuit further includes: A first protection unit is connected to the voltage dividing unit and receives the divided voltage, and stabilizes the divided voltage to protect the first switch.

14. The power supply according to claim 10, characterized in that, The reference voltage adjustment circuit includes: A first resistor circuit, which includes at least one resistor, is connected between the discharge voltage detection circuit and the constant current circuit, receives the DC voltage, adjusts the magnitude of the supply voltage, and determines the magnitude of the discharge current.

15. The power supply according to claim 10, wherein, The constant current drive circuit includes: A second resistor circuit, which includes at least one resistor, provides the drive voltage for driving the constant current circuit.

16. The power supply according to claim 15, characterized in that, The constant current drive circuit further includes: A second protection unit is connected to the second resistor circuit to protect the constant current circuit.

17. The power supply according to claim 10, characterized in that, The constant current circuit includes: A second switch is connected to the reference voltage adjustment circuit and receives the supply voltage; and, A third switch is connected to the second switch; When the second switch is turned on, the third switch provides a discharge path for the discharge current to flow through the discharge path for constant current discharge.

18. The power supply according to claim 9, characterized in that, The AC side circuit includes: An electromagnetic interference filtering circuit that receives the AC input voltage and converts the AC input voltage into a filtered voltage; An input rectifier filtering circuit is connected to the electromagnetic interference filtering circuit, receives the filtered voltage, and converts the filtered voltage into a rectified and filtered voltage; and, A power factor correction conversion circuit is connected to the input rectifier filtering circuit and converts the rectified and filtered voltage into the DC voltage.

19. The power supply according to claim 9, characterized in that, The DC side circuit includes: A DC-DC conversion circuit that receives the DC voltage and converts the DC voltage into a converted voltage; and, An output rectifier filtering circuit is connected to the DC-DC conversion circuit and converts the converted voltage into the DC output voltage.

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