DISCHARGE UNIT

Abstract

A discharge unit for a power converter comprising an inductive element, the discharge unit configured to: detect a voltage difference across the inductive element; and activate a discharge path for the power converter based on the voltage difference.

Description

[0001] The present invention relates to a discharge unit. In particular, the present invention relates to a discharge unit for a power converter comprising an inductive element. BACKGROUND

[0002] Power converters often include an inductive element for storing energy. There are situations where the inductive element stores energy that cannot be delivered to a load or safely discharged as a current through a low-impedance node. In this situation, if the inductive element forces the current into a high-impedance node, it will cause the voltage to rise until a damaging breakdown mechanism occurs. Therefore, a safe means of discharging the inductive element is required.

[0003] Power converters can be used as part of the gate drive unit (GDU) for inverters in electric vehicle applications. Each GDU requires its own power converter with its own inductive element, which requires a safe means of discharging. SUMMARY

[0004] It is desirable to provide an improved discharge unit for a power converter.

[0005] With the increasing electrification of vehicles, it is desirable to design electric vehicle systems that are efficient and cost-effective by improving voltage discharge techniques in power converters.

[0006] According to a first aspect of the invention, a discharge unit for a power converter is provided, comprising an inductive element, the discharge unit being configured to: detect a voltage difference across the inductive element; and activate a discharge path for the power converter based on the voltage difference.

[0007] Optionally, the inductive element is coupled between a first node providing a first voltage and a second node providing a second voltage.

[0008] Optionally, the inductive element comprises at least one of an inductor; a transformer.

[0009] Optionally comprising a voltage detection unit for detecting the voltage difference across the inductive element.

[0010] Optionally, the inductive element is coupled between a first node providing a first voltage and a second node providing a second voltage.

[0011] Optionally, the voltage sensing unit is configured to receive the first voltage and the second voltage; and the voltage difference is the difference between the first voltage and the second voltage.

[0012] Optionally, the voltage detection unit is configured to compare the voltage difference with a threshold voltage; and the discharge unit is configured to activate the discharge path based on the comparison of the voltage difference with the threshold voltage, thereby activating the discharge path based on the voltage difference.

[0013] Optionally, the threshold voltage is a preset value.

[0014] Optionally, the voltage sensing unit comprises at least one row of one or more Zener diodes such that the threshold voltage is proportional to the number of Zener diodes.

[0015] Optionally, the voltage sensing unit is configured to activate the discharge path for the power converter when the voltage difference is greater than the threshold voltage, thereby activating the discharge path based on the comparison of the voltage difference with the threshold voltage.

[0016] Optionally, the voltage sensing unit comprises at least one row of one or more Zener diodes, wherein the threshold voltage is proportional to the number of Zener diodes, such that when the voltage difference is greater than the threshold voltage, a conduction current is conducted through the at least one row of one or more Zener diodes.

[0017] Optionally, the voltage sensing unit comprises a resistive element such that when the line current is passed through the at least one row of one or more Zener diodes, an activation voltage is generated.

[0018] Optionally, the discharge unit is configured to disable the discharge path for the power converter based on the voltage difference.

[0019] Optionally, the voltage sensing unit is configured to compare the voltage difference with a threshold voltage; and the discharging unit is configured to deactivate the discharge path based on the comparison of the voltage difference with the threshold voltage, thereby deactivating the discharge path based on the voltage difference.

[0020] Optionally, the voltage sensing unit is configured to disable the discharge path for the power converter when the voltage difference is less than the threshold voltage, thereby disabling the discharge path based on the comparison of the voltage difference with the threshold voltage.

[0021] Optionally, the voltage sensing unit comprises at least one row of one or more Zener diodes, wherein the threshold voltage is proportional to the number of Zener diodes, such that when the voltage difference is less than the threshold voltage, a conduction current is not conducted through the at least one row of one or more Zener diodes.

[0022] Optionally, the voltage sensing unit comprises a resistive element such that when the conduction current is not conducted through the at least one row of one or more Zener diodes, no activation voltage is generated.

[0023] Optionally, the discharge path includes a first current source.

[0024] Optionally comprising a voltage detection unit for detecting the voltage difference across the inductive element.

[0025] Optionally, the voltage detection unit is configured to compare the voltage difference with a threshold voltage; and the discharge unit is configured to activate the discharge path based on the comparison of the voltage difference with the threshold voltage, thereby activating the discharge path based on the voltage difference.

[0026] Optionally, the voltage sensing unit is configured to activate the discharge path for the power converter when the voltage difference is greater than the threshold voltage, thereby activating the discharge path based on the comparison of the voltage difference with the threshold voltage; and the voltage sensing unit is configured to activate the first current source when the voltage difference is greater than the threshold voltage.

[0027] Optionally, the voltage sensing unit comprises at least one row of one or more Zener diodes, wherein the threshold voltage is proportional to the number of Zener diodes, such that when the voltage difference is greater than the threshold voltage, a current is conducted through the at least one row of one or more Zener diodes.

[0028] Optionally, the voltage sensing unit comprises a resistive element such that when the current is passed through the at least one row of one or more Zener diodes, an activation voltage is generated.

[0029] Optionally, the first current source is activated by the activation voltage.

[0030] Optionally, the first current source comprises a first transistor and a second transistor, wherein both the first and second transistors include a control terminal coupled to the resistive element such that when the activation voltage is generated, both the first and second transistors are turned on.

[0031] Optionally, when both the first and second transistors are turned on, they conduct a first current.

[0032] Optionally, the discharge path includes a clamp switch coupled to the first power source.

[0033] Optionally comprising a voltage detection unit for detecting the voltage difference across the inductive element.

[0034] Optionally, the voltage detection unit is configured to compare the voltage difference with a threshold voltage; and the discharge unit is configured to activate the discharge path based on the comparison of the voltage difference with the threshold voltage, thereby activating the discharge path based on the voltage difference.

[0035] Optionally, the voltage sensing unit is configured to activate the discharge path for the power converter when the voltage difference is greater than the threshold voltage, thereby activating the discharge path based on the comparison of the voltage difference with the threshold voltage; and the discharge unit is configured to close the clamp switch when the voltage difference is greater than the threshold voltage.

[0036] Optionally, the inductive unit is discharged via the clamp switch if the voltage difference is greater than the threshold voltage.

[0037] Optionally, the clamp switch is configured to operate at the threshold voltage.

[0038] Optionally, the voltage sensing unit is configured to activate the first current source when the voltage difference is greater than the threshold voltage.

[0039] Optionally, the voltage sensing unit comprises at least one row of one or more Zener diodes, wherein the threshold voltage is proportional to the number of Zener diodes, such that when the voltage difference is greater than the threshold voltage, a current is conducted through the at least one row of one or more Zener diodes.

[0040] Optionally, the voltage sensing unit comprises a resistive element such that when the current is passed through the at least one row of one or more Zener diodes, an activation voltage is generated.

[0041] Optionally, the first current source is activated by the activation voltage.

[0042] Optionally, the first current source comprises a first transistor and a second transistor, wherein both the first and second transistors include a control terminal coupled to the resistive element such that when the activation voltage is generated, both the first and second transistors are turned on.

[0043] Optionally, when both the first and second transistors are turned on, they conduct a first current.

[0044] Optionally, the clamp switch is a third transistor comprising a control terminal coupled to the first and second transistors.

[0045] Optionally, the clamp switch is configured to turn on when it receives the first current.

[0046] Optionally, the voltage discharge unit is configured to disable the discharge path for the power converter based on the voltage difference.

[0047] Optionally comprising a voltage detection unit for detecting the voltage difference across the inductive element.

[0048] Optionally, the voltage sensing unit is configured to compare the voltage difference with a threshold voltage; and the discharging unit is configured to deactivate the discharge path based on the comparison of the voltage difference with the threshold voltage, thereby deactivating the discharge path based on the voltage difference.

[0049] Optionally, the voltage sensing unit is configured to deactivate the discharge path for the power converter when the voltage difference is less than the threshold voltage, thereby deactivating the discharge path based on the comparison of the voltage difference with the threshold voltage; and the voltage sensing unit is configured to deactivate the first current source when the voltage difference is less than the threshold voltage.

[0050] Optionally, the voltage sensing unit comprises at least one row of one or more Zener diodes, wherein the threshold voltage is proportional to the number of Zener diodes, such that when the voltage difference is greater than the threshold voltage, a current is not conducted through the at least one row of one or more Zener diodes.

[0051] Optionally, the voltage sensing unit comprises a resistive element such that when the current is not passed through the at least one row of one or more Zener diodes, no activation voltage is generated.

[0052] Optionally, the first current source is deactivated because the activation voltage is not generated.

[0053] Optionally, the first current source comprises a first transistor and a second transistor, wherein both the first and second transistors comprise a control terminal coupled to the resistive element such that when the activation voltage is generated, both the first and second transistors are turned on, and when the activation voltage is not generated, both the first and second transistors are turned off.

[0054] Optionally, when both the first and second transistors are turned on, they conduct a first current, and when both the first and second transistors are turned off, they do not conduct the first current.

[0055] Optionally, the discharge path includes a clamp switch coupled to the first power source.

[0056] Optionally, the voltage discharge unit is configured to open the clamp switch when the voltage difference is less than the threshold voltage.

[0057] Optionally, the discharge unit includes a second power source coupled to the clamp switch.

[0058] Optionally, the second current source is configured to open the clamp switch when the voltage difference is less than the threshold voltage.

[0059] Optionally, the second current source includes a resistance element.

[0060] Optionally, the discharge unit includes an isolation device.

[0061] Optionally, the isolation device is coupled to the second node providing the second voltage; and the isolation device is configured to block a conductive path between the first node and the second node when the second node is coupled to ground.

[0062] Optionally, the power converter includes a power switch coupled to ground, the switch configured to operate in an on-state or an off-state.

[0063] Optionally, the inductive element is coupled between a first node providing a first voltage and a second node providing a second voltage; and the power switch is also coupled to the second node providing the second voltage.

[0064] Optionally, the discharge unit includes an isolation device.

[0065] Optionally, the isolation device is coupled to the second node.

[0066] Optionally, the isolation device is configured to block a conductive path between the first node and the second node when the circuit breaker is in the on state and thus the second node is coupled to ground.

[0067] According to a second aspect of the invention, an apparatus is provided, comprising: a power converter comprising an inductive element; and a discharge unit for the power converter, wherein the discharge unit is configured to: detect a voltage difference across the inductive element; and activate a discharge path for the power converter based on the voltage difference.

[0068] Optionally, the device is a gate driver unit for a traction inverter.

[0069] Optionally comprising a chip, wherein the power converter and the discharge unit are implemented on the chip.

[0070] It will be appreciated that the device of the second aspect may include features as set out in relation to the first aspect and may include other features as described herein.

[0071] According to a third aspect of the invention, a method is provided for discharging a power converter comprising an inductive element, the method comprising: detecting a voltage difference across the inductive element; and activating a discharge path for the power converter based on the voltage difference.

[0072] It will be appreciated that the method of the third aspect may include using and / or providing features as set out in the first aspect and / or second aspect and may include other features as described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The description below is given by way of example only and with reference to the accompanying drawings in which: Fig. 1 is a diagram of a prior art reverse power converter; Fig. 2 is a diagram of an exemplary embodiment of a discharge unit for a power converter according to the present disclosure; Fig. 3 is a diagram of another exemplary embodiment of a discharge unit for a power converter according to the present disclosure; Fig. 4(a) is a first exemplary embodiment of a voltage detection unit connected to the discharge unit of Fig. 3 can be used, Fig. 4(b) is a second exemplary embodiment of a voltage detection unit connected to the discharge unit of Fig. 3 can be used; Fig. 4(c) is the second exemplary embodiment of the voltage detection unit when the voltage detection unit detects a voltage difference that is smaller than a threshold voltage; Fig. 5 is a diagram of another exemplary embodiment of a discharge unit for a power converter according to the present disclosure; Fig. 6(a) is a first exemplary embodiment of a voltage sensing unit coupled to a first current source connected to the discharge unit of Fig. 5 can be used; Fig. 6(b) is a second exemplary embodiment of a voltage sensing unit coupled to a first current source connected to the discharge unit of Fig. 5 can be used; Fig. 7 is a diagram of another exemplary embodiment of a discharge unit for a power converter according to the present disclosure; Fig. 8(a) is a diagram of an exemplary embodiment of a voltage sensing unit that enables a discharge path for a power converter; Fig. 8(b) is an exemplary embodiment of a voltage sensing unit that disables a discharge path for a power converter; Fig. 9 is a diagram of another exemplary embodiment of a discharge unit for a power converter according to the present disclosure; Fig. 10 is a diagram of another exemplary embodiment of a discharge unit for a power converter according to the present disclosure; Fig. 11 is a diagram of another exemplary embodiment of a discharge unit for a power converter according to the present disclosure; Fig. 12 is a graphical representation of how the discharge unit of Fig. 11 works; Fig. 13 is a diagram of another exemplary embodiment of a discharge unit for a power converter according to the present disclosure; Fig. 14(a) is a first exemplary embodiment of an isolation device that may be used with any of the discharge units of the present disclosure; Fig. 14(b) is a second exemplary embodiment of an isolation device that may be used with any of the discharge units of the present disclosure; Fig. 15 is a graph showing simulation results using a discharge unit of Fig. 13 as part of a gate driver unit; Fig. 16 is a diagram of an apparatus incorporating any of the discharge units of the present disclosure; and Fig. 17 is a flowchart illustrating a method for discharging a power converter according to the present disclosure. DETAILED DESCRIPTION

[0074] For power converters with an inductive element, such as an inductive element, where the inductive element stores energy that cannot be safely delivered to a load or safely discharged through a low-impedance node, the inductive element forces a current through a high-impedance node, causing the voltage in the circuit to rise until damaging breakdown mechanisms occur. There are several situations where this can occur. For example, when a low-side switch drives an inductive load without a recirculation path for the energy to discharge when the low-side switch is off.

[0075] One type of power converter in which such an unsafe discharge event can occur is a flyback converter.

[0076] Fig. 1 is a diagram of a flyback converter 100 according to the prior art. The flyback converter 100 includes a low-side switch LS coupled between ground GND and a node SW. The flyback converter 100 further includes an inductive element 110. In this exemplary prior art embodiment, the inductive element 110 includes an inductor L LK , which is coupled to a transformer T.

[0077] In normal operating mode, when the low-side switch LS is in an on state, the primary winding of the transformer T is charged. When the low-side switch LS is in the off state, the energy stored on the primary winding is transferred to the secondary winding of the transformer T.

[0078] Any energy that cannot be transferred between the primary and secondary windings is called a leakage inductance L LK which is coupled to the primary winding of the transformer T. Each time the low-side switch LS turns off, the voltage in L LK stored energy cannot be dissipated anywhere. This causes the node SW to fly to a high voltage, which is at least too high for the low-side switch LS and the semiconductor chip that controls the blocking control (in Fig. 1 not shown) can be destructive. A common solution is to place a voltage clamp 120 across the primary side of the transformer T to clamp the voltage of the node SW to a safe value above the input voltage Vin of the flyback converter 100. Then the energy on the stray inductance can discharge safely when the low-side switch LS is turned off. In the Fig. In the flyback converter 100 shown in Figure 1, the voltage clamp 120 is implemented using a combination of Zener diodes and Schottky diodes. In other embodiments, an external resistor-capacitor snubber could be used.

[0079] These solutions can be applied to other types of power converters. The known prior art solutions for safely discharging the energy of the inductor L LK require off-chip components, which increases the cost and size of the circuit.

[0080] Power converters, such as the one in Fig. Flyback converters, as shown in Figure 1, can be used as part of the gate drive unit for an inverter. High-voltage gate drive units (GDUs) drive the switches of inverters in electric vehicle applications. Each GDU requires a specific voltage to drive the gate of the insulated-gate bipolar transistors (IGBTs) or silicon carbide (SiC) power switches. These specific voltages are not available in the system and are instead generated by a power converter, such as a flyback converter. Due to the galvanic isolation requirements needed in automotive systems, at a minimum, each of the inverter's high-side switches must have a separate flyback converter for each GDU. The most common configuration used for electric vehicles is a distributed architecture, where each inverter switch has a GDU with its own flyback converter.This architecture requires 12 external voltage terminals that must be added to the GDUs board. For example, for a 400 V / 100 kW traction inverter, the additional area required for these off-chip voltage terminals is approximately 50 mm. 2 .

[0081] One of the driving requirements in the race for transportation electrification is to design traction inverters with the highest power density (more compact) and reduce costs. Therefore, an improved means of safely discharging the inductive element of a power converter is needed to reduce the cost and area of ​​the circuitry involved.

[0082] Fig. 2 is a diagram of an exemplary embodiment of a discharge unit 200 for a power converter 202 according to a first embodiment of the present disclosure. The power converter 202 includes an inductive element 204. The inductive element 204 is coupled between a first node N1, which provides a first voltage V1, and a second node N2, which provides a second voltage N2. The inductive element 204 may, for example, comprise at least one of an inductor or a transformer. This is not an exhaustive list of elements that may be used.

[0083] The discharge unit 200 is configured to detect a voltage difference V diffacross the energy storage element 204. The voltage difference is the difference between the first voltage V1 and the second voltage V2. The discharge unit 200 is further configured to establish a discharge path DP for the power converter 202 based on the voltage difference V diff to activate.

[0084] Fig. Figure 3 is a diagram of another exemplary embodiment of a discharge unit 200 for a power converter 202 according to a second embodiment of the present disclosure. The power converter 202 is the same as the power converter of Fig. 2, therefore the same labeling has been retained and the components are considered to have the same functionality and significance as for Fig. 2. The discharge unit 200 is the same as that shown in Fig. 2 with the addition of feature 210. Therefore, the same marking has been retained and the components are considered to have the same functionality and significance as for the discharge unit 200 of Fig. 2 is considered to have.

[0085] The discharge unit 200 comprises a voltage detection unit 210 for detecting the voltage difference V diff across the inductive element 204. The energy storage element 204 is coupled between a first node N1, which provides a first voltage V1, and a second node N2, which provides a second voltage V2.

[0086] The voltage detection unit 210 is configured to receive the first voltage V1 and the second voltage V1. The voltage difference V diff, which is detected by the voltage detection unit 210, is the difference between the first voltage V1 and the second voltage V2. The voltage detection unit 210 is further configured to detect the voltage difference V diff with a threshold voltage Vthresh. Depending on this comparison, the discharge unit 210 is configured to activate the discharge path DP for the power converter 200. The discharge path DP is activated when the voltage difference V diff is greater than the threshold voltage. In other words, if V diff (= V2 - V1) > V thresh is, the discharge path DP is active. The discharge unit 210 is further configured to activate the discharge path DP for the power converter 200 based on the voltage difference V diff The discharge path DP is deactivated when the voltage difference V diff is less than the threshold voltage. In other words, if V diff (= V2 - V1) < Vthresh the discharge path DP is not active.

[0087] The threshold voltage V thresh can be a preset value. For example, the threshold voltage V thresh be equal to the maximum breakdown voltage for the components in the discharge unit 200 and the power converter 202. The threshold voltage V thresh can be set by the voltage detection unit 210.

[0088] Fig. Figure 4(a) is a first exemplary embodiment of a voltage sensing unit 210 that can be used with any of the discharge units 200 of the present disclosure. The arrows in the diagram pointing to nodes N1 and N2 illustrate the coupling points of the voltage sensing unit 210 to the nodes N1, N2. It is understood that other couplings may be possible according to the understanding of one skilled in the art. In this first exemplary embodiment of the voltage sensing unit 210, the voltage sensing unit 210 comprises a series of one or more Zener diodes Z to Z n In this embodiment, the threshold voltage is proportional to the number of Zener diodes in the series. In other words, V thresh ∝ n, where n is the total number of Zener diodes in the series.

[0089] Fig. 4(b) is a second exemplary embodiment of a voltage sensing unit 210 that can be used with any of the discharge units 200 of the present disclosure. The arrows in the diagram pointing to nodes N1 and N2 illustrate the coupling points of the voltage sensing unit 210 to the nodes N1, N2. It is understood that other couplings may be possible according to the understanding of one skilled in the art. In this second exemplary embodiment of the voltage sensing unit 210, the voltage sensing unit 210 includes a first series of one or more Zener diodes Z to Z n and a second series of one or more Zener diodes Z' to Z m '. In an exemplary embodiment, the first row and the second row of one or more Zener diodes have the same total number of Zener diodes. In other words, n = m. The threshold voltage V threshwould in this case be proportional to the number of Zener diodes, n = m, in one of the rows. In other words, V thresh ∝ n, where n is the total number of Zener diodes in one of the rows and n = m. In another exemplary embodiment, the first row and the second row of one or more Zener diodes do not have the same total number of Zener diodes. In other words, n is not equal to m. The threshold voltage V thresh would in this case be proportional to the total sum of Zener diodes in each row. In other words, V thresh ∝ (n + m), where n is the total number of Zener diodes in the first row and m is the total number of Zener diodes in the second row. The voltage sensing unit 210 further includes a resistive element R coupled between the first row of one or more Zener diodes and the second row of one or more Zener diodes. The resistive element could be a resistor, for example.

[0090] If the voltage difference V diff greater than the threshold voltage Vthresh, a conduction current I c through the first row and the second row of one or more Zener diodes and through the resistance element R, so that an activation voltage V a The voltage detection unit 210 is shown as a combination of (integrated) Zener diodes and resistors. The voltage detection unit 210 has the function of measuring the current I c only to be conducted if V diff (= V2 - V1) the threshold voltage V thresh has reached.

[0091] Fig. Figure 4(c) is an alternative schematic diagram to the exemplary embodiment of the voltage sensing unit 210 of Fig. 4(b) for the operating configuration when no current is passed through the voltage detection unit 210. The voltage detection unit 210 is the same as the voltage detection unit of Fig. 4(b), therefore the same marking has been retained and the components are considered to have the same functionality and meaning as for Fig. 4(b). The arrows in the diagram pointing to nodes N1 and N2 illustrate the coupling points of the voltage sensing unit 210 to nodes N1, N2. It is understood that other couplings may be possible according to the understanding of one skilled in the art. If the voltage difference V diff less than the threshold voltage V thresh is, the line current I c not passed through the first row of one or more Zener diodes or the second row of one or more Zener diodes. Thus, no activation voltage V agenerated via the resistance element R.

[0092] Fig. 5 is a diagram of another exemplary embodiment of a discharge unit 200 for a power converter 202 according to a third embodiment of the present disclosure. The power converter 202 is the same as the power converter of Fig. 3, therefore the same labeling has been retained and the components are considered to have the same functionality and significance as for Fig. 3. The discharge unit 200 is the same as that shown in Fig. 3 with the addition of feature 220. Therefore, the same marking has been retained and the components are considered to have the same functionality and significance as for the discharge unit 200 of Fig. 3. The discharge path DP comprises a first current source 220 coupled to the voltage detection unit 210.

[0093] The voltage detection unit 210 is configured to activate the first current source 220 when the voltage difference V diff greater than the threshold voltage V thresh so that when the first current source 220 is activated, the discharge path DP for the power converter 200 is also activated.

[0094] Fig. Figure 6(a) is a first exemplary embodiment of a voltage sensing unit 210 coupled to a first current source 220. The exemplary embodiment of this figure can be used with any discharge unit 200 of the present disclosure. The arrows in the diagram pointing to nodes N1 and N2 illustrate the coupling points of the voltage sensing unit 210 to the nodes N1, N2. It is understood that other couplings may be possible according to the understanding of one skilled in the art. The voltage sensing unit 210 includes a first series of one or more Zener diodes Z to Z n and a second series of one or more Zener diodes Z' to Z m '. In an exemplary embodiment, the first row and the second row of one or more Zener diodes have the same total number of Zener diodes. In other words, n = m. The threshold voltage V threshwould in this case be proportional to the number of Zener diodes, n = m, in one of the rows. In other words, V thresh ∝ n × V zener , where n is the total number of Zener diodes in one of the rows and n = m. The voltage V zener is the breakdown voltage of each Zener diode. In another exemplary embodiment, the first row and the second row of one or more Zener diodes do not have the same total number of Zener diodes. In other words, n is not equal to m. The threshold voltage V thresh would in this case be proportional to the total sum of Zener diodes in each row. In other words, V thresh ∝ (n + m) × V zener , where n is the total number of Zener diodes in the first row and m is the total number of Zener diodes in the second row. The voltage V zeneris the breakdown voltage of each Zener diode. The voltage sensing unit 210 further includes a resistive element R coupled between the first row of one or more Zener diodes and the second row of one or more Zener diodes. The resistive element could be a resistor, for example.

[0095] If the voltage difference V diff greater than the threshold voltage V thresh is, a line current I c through the first row and the second row of one or more Zener diodes and through the resistance element R, so that an activation voltage V a The first current source 220 is then activated by the activation voltage V a activated. The voltage detection unit 210 has the function of measuring the current I c only to be conducted if V diff (= V2 - V1) the threshold voltage V thresh has been reached. Therefore, the first current source is only activated when Vdiff (= V2 - V1) the threshold voltage V thresh has reached.

[0096] Fig. Figure 6(b) is a second exemplary embodiment of a voltage sensing unit 210 coupled to a first current source 220. The exemplary embodiment of this figure can be used with any discharge unit 200 of the present disclosure. The arrows in the diagram pointing to nodes N1 and N2 illustrate the coupling points of the voltage sensing unit 210 to nodes N1, N2. It is understood that other couplings may be possible according to the understanding of one skilled in the art. The voltage sensing unit 210 shown in this figure is the same as that shown in Fig. 6(a), therefore the same labeling has been retained and the components are considered to have the same functionality and meaning as for Fig. 6(a).

[0097] The first current source 220 includes a first transistor T1, which includes a control terminal, and a second transistor T2, which includes a control terminal. The first transistor T1 is coupled in series with the second transistor T2. Both the first transistor T1 and the second transistor T2 are coupled via their control terminals to the resistance element R of the voltage detection unit 210.

[0098] If the activation voltage V a is generated, both the first transistor T1 and the second transistor T2 are turned on and they both conduct a first current I1. Thus, when the voltage difference V diff less than the threshold voltage V thresh and no activation voltage V a is generated, the first transistor T1 and the second transistor T2 are switched off.

[0099] Fig. Figure 7 is a diagram of another exemplary embodiment of a discharge unit 200 for a power converter 202 according to a fourth embodiment of the present disclosure. The power converter 202 is the same as the power converter of Fig. 5, therefore the same labeling has been retained and the components are considered to have the same functionality and significance as for Fig. 5. The discharge unit 200 is the same as that shown in Fig. 5 with the addition of feature SW. Therefore, the same marking has been retained and the components are considered to have the same functionality and significance as for the discharge unit 200 of Fig. 5. The discharge path DP includes a clamp switch SW coupled to the first current source 220.

[0100] The voltage detection unit 210 is configured to activate the discharge path DP for the power converter 200 when the voltage difference V diff = (V2 - V1) greater than the threshold voltage V thresh If the voltage difference V diff greater than the threshold voltage V thresh , the voltage detection unit 210 is configured to close the clamp switch SW, thereby activating the discharge path DP. Once the clamp switch SW is closed, the inductive unit 204 is discharged via the clamp switch SW. The clamp switch SW is configured to be at the threshold voltage V thresh to work so that when the clamp switch is closed (ON), it contacts the inductive element at a maximum voltage equal to the threshold voltage V thresh discharges. The voltage detection unit 210 is configured to activate the first current source 220 when the voltage difference V diff greater than the threshold voltage Vthresh When the first current source 220 is activated, the clamp switch SW is closed and the inductive element 204 is discharged via the clamp switch SW.

[0101] The discharge unit 200 is also configured to determine the discharge path DP for the power converter 200 based on the voltage difference V diff to deactivate. The discharge unit 200 is configured to open the clamp switch SW when the voltage difference V diff is less than the threshold voltage Vthresh, thereby disabling the discharge path DP for the power converter 200.

[0102] The voltage detection unit 210 is configured to deactivate the discharge path DP when the voltage difference V diff less than the threshold voltage V thresh If the voltage difference V diff less than the threshold voltage V threshThe voltage detection unit 210 is configured to deactivate the first current source 220. The clamp switch SW is coupled to the first current source 220. Therefore, when the first current source 220 is deactivated, the clamp switch is opened.

[0103] In summary, the clamp switch SW acts to clamp the voltage generated by the inductive element attempting to discharge the stored magnetic energy. It does this by providing a safe discharge path for the current while maintaining the clamped voltage at a safe value. Fig. Figure 8(a) is a diagram illustrating an exemplary embodiment of a voltage sensing unit 210 that activates a discharge path DP for a power converter 200. The arrows in the diagram pointing to nodes N1 and N2 illustrate the coupling points of the voltage sensing unit 210 to nodes N1, N2. It is understood that other couplings may be possible according to the understanding of one skilled in the art. Another arrow pointing to the inductive element 204 illustrates the coupling point of the discharge path DP to the power converter 200. It is understood that other couplings may be possible according to the understanding of one skilled in the art.

[0104] The voltage detection unit 210 comprises a first series of one or more Zener diodes Z to Z n and a second series of one or more Zener diodes Z' to Z m'. In an exemplary embodiment, the first row and the second row of one or more Zener diodes have the same total number of Zener diodes. In other words, n = m. The threshold voltage V thresh would in this case be proportional to the number of Zener diodes, n = m, in one of the rows. In other words, V thresh ∝ n × V zener , where n is the total number of Zener diodes in one of the rows and n = m. The voltage V zener is the breakdown voltage of each Zener diode. In another exemplary embodiment, the first row and the second row of one or more Zener diodes do not have the same total number of Zener diodes. In other words, n is not equal to m. The threshold voltage V thresh would in this case be proportional to the total sum of Zener diodes in each row. In other words, V thresh ∝ (n + m) × V zener, where n is the total number of Zener diodes in the first row and m is the total number of Zener diodes in the second row. The voltage V zener is the breakdown voltage of each Zener diode. The voltage sensing unit 210 further includes a resistive element R coupled between the first row of one or more Zener diodes and the second row of one or more Zener diodes. The resistive element could be a resistor, for example. When the voltage difference V diff greater than the threshold voltage V thresh is, a line current I c through the first row and the second row of one or more Zener diodes and through the resistance element R, so that an activation voltage V a The voltage detection unit 210 is shown as a combination of (integrated) Zener diodes and resistors. The voltage detection unit 210 has the function of measuring the current I conly to be conducted if V diff (= V2 - V1) has reached the threshold voltage Vthresh.

[0105] The discharge path DP includes the first current source coupled to a clamp switch SW.

[0106] The first current source 220 comprises a first transistor T1, which includes a control terminal, and a second transistor T2, which includes a control terminal. The first transistor T1 is coupled in series with the second transistor T2. Both the first transistor T1 and the second transistor T2 are coupled via their control terminals to the resistance element R of the voltage detection unit 210. When the activation voltage V a is generated, both the first transistor T1 and the second transistor T2 are turned on and they both conduct a first current I1.

[0107] In this exemplary embodiment, the clamp switch SW is a third transistor that includes a control terminal. The control terminal of the clamp switch SW is coupled to the first and second transistors. The clamp switch SW is configured to turn on (close) when it receives the first current I1. The clamp switch SW is further configured to operate at a maximum voltage that exceeds the threshold voltage V thresh If the voltage difference V diff = (V2 - V1) reaches the threshold voltage, the conduction current I c begin to flow through the voltage detection unit 210 and the activation voltage V a which is needed to activate the first current source 220. If the clamp switch SW is correctly sized, the control terminal of SW will be at the threshold voltage V threshto allow the clamp switch SW to operate in saturation while the inductive element 204 is discharged.

[0108] The components of the voltage sensing unit 210, the first current source 220 and the clamp switch SW are selected to withstand the appropriate voltage with which they are to be used.

[0109] Fig. Figure 8(b) is an alternative schematic diagram of the voltage sensing unit 210 of Fig. 8(a), wherein the voltage sensing unit 210 deactivates a discharge path DP for a power converter 200. The arrows in the diagram pointing to nodes N1 and N2 illustrate the coupling points of the voltage sensing unit 210 to the nodes N1, N2. It is understood that other couplings may be possible according to the understanding of the person skilled in the art. Another arrow pointing to the inductive element 204 illustrates the coupling point of the discharge path DP to the power converter 200. It is understood that other couplings may be possible according to the understanding of the person skilled in the art. The voltage sensing unit 210 of this figure is the same as that of Fig. 8(a), therefore the same marking has been retained and the components are considered to have the same functionality and meaning as for Fig. 8(a). The discharge path DP comprises a first current source 220 coupled to a clamp switch SW. The first current source 220 and the clamp switch SW are the same as those shown in Fig. 8(a), therefore the same marking has been retained and the components are considered to have the same functionality and meaning as for Fig. 8(a).

[0110] If the voltage difference V diff less than the threshold voltage V thresh is, the line current I c not passed through the first row and the second row of one or more Zener diodes. Thus, no activation voltage V a via the resistance element R. The voltage detection unit 210 has the function of measuring the current I c only to be conducted if V diff (= V2 - V1) the threshold voltage V thresh has been reached. If V diffis less than the threshold voltage, no current I c led.

[0111] Since the activation voltage V a is not generated, the first current source 220 is deactivated. If the activation voltage V a is not generated, the first T1 and the second T2 transistors are turned off. When both the first T1 and the second T2 transistors are turned off, they do not conduct the first current I1. Once the inductive element 204 is discharged, the voltage difference V diff back below the threshold voltage V thresh . This causes the first current source 220 to be deactivated and the clamp switch SW to be turned off.

[0112] Fig. 9 is a diagram of another exemplary embodiment of a discharge unit 200 for a power converter 202 according to a fifth embodiment of the present disclosure. The power converter 202 is the same as the power converter of Fig. 7, therefore the same marking has been retained and the components are considered to have the same functionality and significance as for Fig. 5. The discharge unit 200 is the same as that for Fig. 7 with the addition of features 230 and 232. Therefore, the same marking has been retained and the components are considered to have the same functionality and significance as for the discharge unit 200 of Fig. 7. The discharge unit 200 further comprises a second current source 230 coupled to the clamp switch SW.

[0113] The second current source 230 is configured to open the clamp switch SW when the voltage difference Vdiff = (V2 - V1) less than the threshold voltage V thresh The second current source 230 includes a resistive element 232. The resistive element 232 can be implemented as a resistor. This would be the simplest implementation, as it makes the second current source 230 always active without requiring additional signals. The resistive element 232 can be implemented in any way that provides a current strong enough to keep the clamp switch off (open) when the voltage difference V diff less than the threshold voltage V thresh As soon as the inductive element 204 is discharged, the voltage difference V diff below the threshold voltage V threshThis deactivates the first current source 220, and the second current source keeps the clamp switch SW open (off). The clamp switch SW will naturally transition to the deactivated state, drawing no quiescent current and requiring no control signal to operate.

[0114] Fig. 10 is a diagram of another exemplary embodiment of a discharge unit 200 for a power converter 202 according to a sixth embodiment of the present disclosure. The power converter 202 is the same as the power converter of Fig. 2, therefore the same marking has been retained and the components are considered to have the same functionality. The discharge unit 200 is the same as that shown in Fig. 2 with the addition of feature 240. Therefore, the same marking has been retained and the components are considered to have the same functionality and significance as for the discharge unit 200 of Fig. 2. It is understood that the additional feature 240 may additionally be applied to any discharge unit 200 described in the present disclosure.

[0115] The discharge unit 200 includes an isolation device 240. The isolation device 240 is coupled to the second node N2, which provides the second voltage V2. The isolation device 240 is configured to block a conductive path between the first node N1 and the second node N2 when the second node N2 is coupled to ground.

[0116] Fig. 11 is a diagram of another exemplary embodiment of a discharge unit 200 for a power converter 202 according to a seventh embodiment of the present disclosure. The discharge unit 200 is understood to mean the same as any of the other exemplary embodiments of a discharge unit in the present disclosure. Therefore, the same labeling has been retained, and the components are considered to have the same meaning and functionality as previously described. It is understood that any of the features of the exemplary embodiments described in the present disclosure may be applied to any of the discharge units 200 illustrated in this disclosure.

[0117] The power converter 202 includes an inductive element 204 and a power switch LS coupled to ground GND. The inductive element 204 is coupled between a first node N1, which provides a first voltage VIN, and a second node N2, which provides a second voltage VSW. It is understood that the first node N1 and the second node N2 are equivalent to the first node N1 and the second node N2 of other embodiments of the power converter 202, and that the first voltage VIN and the second voltage VSW are equivalent to the first voltage V1 and the second voltage V2 of other embodiments of the power converter 202. The power switch LS is also coupled to the second node N2, which provides the second voltage VSW. The power switch LS is configured to operate in an on-state or an off-state. When the circuit breaker LS is in the on state, the inductive element 204 is charged.When the circuit breaker LS is in the off state, the inductive element 204 is discharged.

[0118] The discharge unit 200 includes an isolation device 240. The isolation device is also coupled to the second node N2. The isolation device may, for example, be a passive diode. The isolation device 240 is configured to block a conductive path between the first node N1 and the second node N2 when the second node N1 is coupled to ground, for example, when the power switch LS is in the on state.

[0119] The voltage detection unit 210 detects the difference between the second voltage VSW and the first voltage VIN and compares it with a threshold voltage V thresh . If the difference (VSW - VIN) is greater than the threshold voltage V threshis, the first current source 220 is activated (CLAMP-ON) and the clamp switch SW is closed (ON), so that the inductive element 204 is discharged via the discharge path DP. If the difference (VSW - VIN) is less than the threshold voltage V thresh is deactivated, the first current source 220 is deactivated and the clamp switch SW becomes open (OFF), so that the discharge path DP is also deactivated.

[0120] In the exemplary embodiment of Fig. 11, the discharge unit 200 is shown as an on-chip solution applied to a power converter 202. The clamp switch SW is a transistor. The power converter 202 in Fig. 11 is shown as a flyback converter, but could be any type of DC power converter. For example, it could be a boost converter.

[0121] Fig. 12 is a timing graph showing how the Fig. 11 shown voltage detection unit 200 for the power converter 202 operates.

[0122] The upper trace SIG1 is a waveform of a control signal that controls the operation of the circuit breaker LS. Before point A, the waveform of SIG1 is high and the circuit breaker LS is configured in the on state. Therefore, the inductive element 204 is charged. After point A, the waveform of SIG1 is low and the circuit breaker LS is configured in the off state.

[0123] The middle diagram SIG2 shows the voltage VSW at the second node N2 compared to the voltage VIN at the first node N1. Before point A, the voltage difference V diff between VSW and VIN is below the threshold voltage Vthresh, therefore the discharge path DP is deactivated. When the power switch LS goes into the off state, the voltage at the second node N2 rises by an amount Δvactive_clamp above the voltage at the first node N1. Therefore, the voltage difference Vdiff greater than the threshold voltage Vthresh and the discharge path DP is activated.

[0124] The lower diagram SIG3 shows the current through the inductive element 204. Before point A, when the circuit breaker LS is closed, the inductive element 204 is charged, and therefore the current SIG3 increases. At point A, the inductive element 204 begins to discharge through the activated discharge path P. Therefore, the current SIG3 decreases. It decreases by an amount equal to the sum of I_Vsw_sense, I_on, and I_clamp. These are the currents flowing through the voltage sensing unit 210, the first current source 220, and the clamping switch SW.

[0125] If SIG2 is below the selected threshold voltage V thresh, the first current source 220 is inactive. The second current source 230 maintains the voltage across the control terminal of the clamp switch SW at zero, so that the current through the clamp switch I_clamp is zero. The discharge unit 200 does not interfere with the normal operation of the power converter 202 and draws no current at all.

[0126] When the power switch LS is turned off, a stray inductance of the inductive element 204 continues to force a current into the second node N2. Therefore, the voltage at this node begins to rise. At the selected threshold voltage V thresh the voltage detection unit 210 activates the first current source 220. If negative feedback is correctly implemented, the control terminal of the clamp switch SW is closed at the threshold voltage V threshso that the clamp switch SW is in saturation with a drain-source voltage equal to ΔVactive clamp and the clamp switch SW is able to dissipate the energy stored in the inductive element 204 while maintaining the voltage at the second node N2 at the desired clamped voltage.

[0127] Fig. Figure 13 is another exemplary embodiment of a discharge unit 200 for a power converter 202 according to an eighth embodiment of the present disclosure. The discharge unit 200 of this figure is considered to be any of the discharge units described in the present disclosure; as such, the same labeling has been retained, and the components are considered to have the same meaning and functionality as previously described. It should be understood that any of the features in the exemplary embodiments previously described in the present disclosure may be applied to any of the discharge units 200 of this disclosure.

[0128] In this exemplary embodiment, the inductive element 204 of the power converter 202 is illustrated as an inductor. The isolation device 240 is implemented as a passive diode D. However, the isolation device 240 may be any element capable of blocking conduction from the first node N1 to the second node N2 when the second node N2 is coupled to ground GND when the power switch LS is turned on.

[0129] The isolation device 240 could also be an active diode. Fig. 14(a) and Fig. 14(b) show exemplary embodiments of active diodes that may be used as part of the isolation device 240 in any of the discharge units 200 of the present disclosure.

[0130] Fig. Figure 14(a) is a first exemplary embodiment of an isolation device 240 that can be used with any of the discharge units 200 of the present disclosure, as understood by those skilled in the art. The first exemplary embodiment of the isolation device 240 shown in Fig. 14(a) includes a first transistor 1400, a second transistor 1402, a first diode 1404, and a second diode 1406. The first 1400 and second 1402 transistors each have a source terminal and a drain terminal. The first 1400 and second 1402 transistors are coupled in series, such that they are coupled to each other via their source terminals. The first diode 1404 is coupled in parallel across the source and drain terminals of the first transistor 1400, and the second diode 1406 is coupled in parallel across the source and drain terminals of the second transistor 1402.

[0131] Fig. 14(b) is a second exemplary embodiment of an isolation device 240 that can be used with any of the discharge units 200 of the present disclosure, as understood by those skilled in the art. The second exemplary embodiment of the isolation device 240 shown in Fig. 14(b), includes a first transistor 1410, a first diode 1412, a second diode 1414, and a resistor 1416. The first transistor 1410 includes a source terminal, a drain terminal, and a control terminal. The second diode 1414 is coupled in series to the control terminal of the first transistor 1410, and the resistor 1416 is coupled to the source terminal of the first transistor 1410.

[0132] With further reference to Fig. In Figure 13, the voltage detection unit 210 is shown as a combination of (integrated) Zener diodes and resistors. However, the voltage detection unit 210 could be any of the embodiments described herein. The voltage detection unit 210 has the function of conducting current only when the voltage difference V diff between the voltage VSW at the second node N2 and the voltage VIN at the first node N1 has reached the threshold voltage, and consequently to activate the first current source 220 with a negative feedback that prevents the voltage at the second node N2 from drifting away.

[0133] The second current source 230 is implemented as a resistor because it is the simplest implementation, as it always makes the second current source 230 active without requiring additional signals. However, it can be implemented in any other way that provides a current strong enough to keep the control terminal of the clamp switch SW at zero when the discharge path must remain deactivated. For example, the second current source can be implemented using transistors.

[0134] Once the inductive element 204 is discharged, the voltage difference between VSW and VIN drops below the threshold voltage again, causing the first current source 220 to deactivate and the second current source 230 to hold the control terminal of the clamp switch SW at zero. Thus, the clamp switch SW naturally transitions to the deactivated state, drawing no quiescent current and requiring no control signal to operate.

[0135] The voltage across the clamp switch SW is therefore defined as: ΔV active clamp=Vzb+Vreg+Vzt+VD

[0136] Where Vzb is the threshold voltage for the first row of Zener diodes in the voltage detection unit 210, Vzt is the threshold voltage for the second row of Zener diodes, Vreg is the activation voltage (it is equivalent to V a) and VD is the voltage across the isolation device 240. Note that the activation voltage can also be defined with respect to the first transistor M (T1) and the second transistor P (T2) of the first current source 220. The activation voltage is also equal to VSGp + VGSm, which are the control terminal voltages of the first M and second DP transistors. The voltage sensing unit 210 can be implemented as a combination of any number of different components to generate the desired threshold voltage. Any combination of Zener diodes, resistors, and diode-connected transistors can be used to define the threshold voltage.

[0137] Those skilled in the art will be able to recognize and analyze the built-in negative feedback that prevents the voltage VSW at the second node N2 from drifting away from ΔV active clamp. When the voltage at the second node N2 reaches ΔV active clamp, a conduction current will begin to flow through the voltage sensing unit 210, generating the activation voltage Vreg needed to activate I_on. If the clamp switch SW is properly sized, its control terminal will be driven at the correct voltage to allow the clamp switch SW to operate in saturation with a drain-source voltage equal to (ΔV active clamp - VD) while the inductive element 204 is discharged. If the voltage at the second node N2 rises above ΔV active clamp, the current through the voltage sensing block 210 would increase, causing Vreg to rise and, therefore, the current of the first current source 220 to increase.This would cause the control terminal voltage of the clamp switch SW to increase and the current through the clamp switch I_clamp to increase, which would have the counteracting effect of reducing the voltage at the second node N2.

[0138] It is preferred that the components of the disclosed circuit be selected to withstand the appropriate operating voltage of the system, as understood by one skilled in the art.

[0139] In the specific case of high-voltage gate drive units (GDUs), the discharge unit 200 of the present disclosure enables the integration of both the power converter control (in this case, a blocking control) and the voltage clamp (of the discharge unit) onto the GDU chip, reducing the complexity and area of ​​the GDU board.

[0140] Fig. 15 is a graph showing simulation results using the discharge unit 200 of Fig. 13 as part of a gate driver unit (GDU). The simulation was performed over all process and temperature corners of the discharge unit 200 and the power converter 200 (implemented as a flyback converter) for the case when a 1uH inductive element 204 is charged up to approximately 2A.

[0141] When the circuit breaker LS is turned off, the discharge unit 204 reacts to clamp the second node N2 and enables a discharge path (I_on and I_Vsw_sense, not shown here).

[0142] For the particular process used in these simulations, the ΔV active clamp spreads over corners from a minimum of approximately 16 V to a maximum of approximately 21.6 V. These minimum and maximum limits must be chosen such that the lower limit does not impair normal operation of the power converter, and the upper limit must remain below the voltage that compromises the reliability of the devices and components that must withstand it. This spread can also be reduced by careful choice of the components used in the voltage sensing unit 210 and good layout practices. In cases where the ΔV active clamp must be very accurate, trimming strategies can be employed in the voltage sensing unit 210.

[0143] In the specific case of the isolated high-voltage GDU for traction inverters, it has been estimated that the discharge unit 200 of the present disclosure only accounts for about 6% of the chip area of ​​the primary side of the isolated GDU.

[0144] Fig. 16 is a diagram of a device 400 according to a ninth embodiment of the present disclosure. The device 400 includes a power converter 202 comprising an inductive element 204 and a discharge unit 200 for the power converter 202. The discharge unit 200 may be any of the embodiments described in the present disclosure. The device 400 further includes a chip 410. The discharge unit 200 and the power converter 202 are implemented on the chip 410. The discharge unit 200 is configured to generate a voltage difference V diffacross the inductive element 204 and to establish a discharge path DP for the power converter 202 based on the voltage difference V diff to activate.

[0145] The device 400 could, for example, be a gate driver unit for a traction inverter.

[0146] Fig. 17 is a flowchart illustrating a method for discharging a power converter including an inductive element according to a tenth embodiment of the present disclosure.

[0147] In step 510, a voltage difference across the inductive element is detected. Then, in step 520, a discharge path for the power converter is activated based on the voltage difference.

[0148] It is understood that power converters of the present disclosure may be flyback converters for gate drive units. Further embodiments may relate to power converters for other applications and for other input voltages, as understood by those skilled in the art.

[0149] Various improvements and modifications may be made without departing from the scope of the disclosure.

[0150] One skilled in the art will recognize that variations of the disclosed arrangements are possible without departing from the disclosure. Accordingly, the above description of the specific embodiments is provided by way of example only and not for purposes of limitation. It will be apparent to one skilled in the art that minor modifications may be made without significant changes to the described operation.

Claims

[1] A discharge unit for a power converter comprising an inductive element, the discharge unit being configured to: Detecting a voltage difference across the inductive element; and Activating a discharge path for the power converter based on the voltage difference. [2] Discharge unit according to claim 1, comprising a voltage detection unit for detecting the voltage difference across the inductive element. [3] The discharge unit of claim 2, wherein the inductive element is coupled between a first node providing a first voltage and a second node providing a second voltage. [4] Discharge unit according to claim 3, wherein: the voltage detection unit is configured to receive the first voltage and the second voltage; and the voltage difference is the difference between the first voltage and the second voltage. [5] Discharge unit according to claim 2, wherein: the voltage detection unit is configured to compare the voltage difference with a threshold voltage; and the discharge unit is configured to activate the discharge path based on the comparison of the voltage difference with the threshold voltage, thereby activating the discharge path based on the voltage difference. [6] The discharge unit of claim 2, wherein the discharge unit is configured to deactivate the discharge path for the power converter based on the voltage difference. [7] Discharge unit according to claim 6, wherein: the voltage detection unit is configured to compare the voltage difference with a threshold voltage; and the discharge unit is configured to deactivate the discharge path based on the comparison of the voltage difference with the threshold voltage, thereby deactivating the discharge path based on the voltage difference. [8] Discharge unit according to claim 7, wherein: the voltage sensing unit is configured to deactivate the discharge path for the power converter when the voltage difference is less than the threshold voltage, thereby deactivating the discharge path based on the comparison of the voltage difference with the threshold voltage. [9] The discharge unit of claim 2, wherein the discharge path comprises a first current source. [10] Discharge unit according to claim 9, wherein: the voltage detection unit is configured to activate the discharge path for the power converter when the voltage difference is greater than the threshold voltage, thereby activating the discharge path based on the comparison of the voltage difference with the threshold voltage; and the discharge unit is configured to close the clamp switch when the voltage difference is greater than the threshold voltage. [11] Discharge unit according to claim 10, wherein the inductive unit is discharged via the clamp switch when the voltage difference is greater than the threshold voltage. [12] The discharge unit of claim 9, wherein the voltage discharge unit is configured to deactivate the discharge path for the power converter based on the voltage difference. [13] Discharge unit according to claim 12, wherein: the voltage detection unit is configured to compare the voltage difference with a threshold voltage; and the discharge unit is configured to deactivate the discharge path based on the comparison of the voltage difference with the threshold voltage, thereby deactivating the discharge path based on the voltage difference. [14] Discharge unit according to claim 13, wherein: the voltage sensing unit is configured to deactivate the discharge path for the power converter when the voltage difference is less than the threshold voltage, thereby deactivating the discharge path based on the comparison of the voltage difference with the threshold voltage; and the voltage detection unit is configured to deactivate the first current source when the voltage difference is less than the threshold voltage. [15] Discharge unit according to claim 14, wherein the discharge unit comprises: a second power source coupled to the clamp switch, whereby: the second current source is configured to open the clamp switch when the voltage difference is less than the threshold voltage. [16] Device comprising: a power converter comprising an inductive element; and a discharge unit for the power converter, the discharge unit being configured to: Detecting a voltage difference across the inductive element; and Activating a discharge path for the power converter based on the voltage difference. [17] A method of discharging a power converter comprising an inductive element, the method comprising: Detecting a voltage difference across the inductive element; and Activating a discharge path for the power converter based on the voltage difference.

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