CN209016697U - The current foldback circuit of power conversion system and power switch tube - Google Patents
The current foldback circuit of power conversion system and power switch tube Download PDFInfo
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- CN209016697U CN209016697U CN201821609862.4U CN201821609862U CN209016697U CN 209016697 U CN209016697 U CN 209016697U CN 201821609862 U CN201821609862 U CN 201821609862U CN 209016697 U CN209016697 U CN 209016697U
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Abstract
The utility model provides the current foldback circuit of a kind of power conversion system and power switch tube, comprising: detection flows through the sampling module of power switch tube electric current；The over-current detection module of flow control signals is obtained based on the electric current for flowing through the power switch tube；The drive module that driving power switching tube turns off when overcurrent；Slow down the soft switching protective module of the turn-off speed of power switch tube when overcurrent.When the electric current for flowing through power switch tube is greater than the set value, control power switch tube shutdown, while slowing down the turn-off speed of power switch tube, avoid voltage overshoot.The power conversion system of the utility model and the current foldback circuit detection of power switch tube flow through the electric current of power switch tube; and overcurrent protection is executed according to the electric current detected; and executing the turn-off speed for slowing down power switch tube while overcurrent protection; the voltage overshoot in the power switch tube is avoided, and then improves the stability and safety of power conversion system.
Description
Technical field
The utility model relates to circuit design fields, more particularly to a kind of power conversion system and the mistake of power switch tube
Stream protection circuit.
Background technique
Power conversion technology is the emerging electronic technology applied to electron electric power field, passes through power switch tube pair
Electric energy is converted and is controlled.In order to inhibit the generation of harmonic wave, while increase power factor, power inverter is introduced into frequency conversion drive
In dynamic system.Due to the complicated multiplicity of the working environment of frequency changing driving system, with operation power is wide, frequency is high and the fluctuation of load is big
The features such as, therefore, very high requirement is proposed to the reliability of power inverter.
In general, power inverter main circuit can generate overshoot current when there is operation irregularity, overshoot current may cause function
Power switch tube in rate inverter main circuit is breakdown.Power conversion is often controlled by current foldback circuit in the prior art
Power switch tube shutdown in device main circuit, the purpose that overcurrent protection is carried out to power switch tube is realized with this.But overshoot electricity
Outflow is current, and overshoot voltage occurs in the rapidly switching off may result in without control of power switch tube on switching tube, works as overshoot voltage
More than power switch tube the pressure-resistant limit when, overshoot voltage is equally possible to cause power switch tube breakdown.
Therefore, overvoltage protection how is taken into account while realizing overcurrent protection, realizes comprehensive protection to power switch tube,
Improve the reliability of power inverter, it has also become one of those skilled in the art's urgent problem to be solved.
Utility model content
In view of the foregoing deficiencies of prior art, the purpose of this utility model is to provide a kind of power conversion system and
The current foldback circuit of power switch tube, overshoot voltage pair caused by being rapidly switched off when for solving overcurrent protection in the prior art
The problem of damage of power switch tube.
In order to achieve the above objects and other related objects, the utility model provides a kind of overcurrent protection electricity of power switch tube
The current foldback circuit on road, the power switch tube includes at least:
Sampling module is connect with power switch tube, and detection flows through the electric current of the power switch tube；
An at least over-current detection module, connects the output end of the sampling module, based on flowing through the power switch tube
Electric current output phase should cross flow control signals；
Drive module is connected to the output end of the over-current detection module, when the electric current mistake for flowing through the power switch tube
When stream, the power switch tube shutdown is driven based on the corresponding flow control signals of crossing；
An at least soft switching protective module corresponds with the over-current detection module, is connected to each over-current detection
The output end of module controls the function based on corresponding flow control signals of crossing when flowing through the overcurrent of the power switch tube
The turn-off speed of rate switching tube avoids the voltage overshoot in the power switch tube.
Optionally, the power switch tube includes insulated gate bipolar transistor.
Optionally, the over-current detection module includes comparator and first switch；
The input terminal of the comparator is separately connected the sampling module and a reference voltage, the output end of the comparator
Connect the control terminal of the first switch；One end connection of the first switch is with reference to ground, and the other end is as the over-current detection
The output end of module；The output end of the sampling module is compared by the comparator with the reference voltage, and controls institute
Flow control signals should be crossed by stating first switch output phase.
More optionally, the over-current detection module further includes second switch；
The output end of the comparator connects the control terminal of the first switch and the second switch；The first switch
One end connection with reference to ground, first output end of the other end as the over-current detection module；One end of the second switch connects
It connects with reference to ground, second output terminal of the other end as the over-current detection module；First output end of the over-current detection module
And second output terminal is separately connected the drive module and the soft switching protective module.
Optionally, the soft switching protective module receives the mistake flow control signals of the over-current detection module output, is used for
When flowing through the overcurrent of the power switch tube, based on the corresponding electric discharge crossed flow control signals and increase the power switch tube
Capacitor slows down the turn-off speed of the power switch tube with this.
More optionally, the soft switching protective module includes third switch and first capacitor；
The third switch and the first capacitor are series between the control terminal of the power switch tube and reference ground, institute
The control terminal for stating third switch connects the output end of the over-current detection module.
More optionally, the soft switching protective module further includes first resistor, second resistance, 3rd resistor and the one or two pole
Pipe；
One end of the first resistor connects the connecting node of the third switch and the first capacitor, other end connection
One predeterminated voltage；One end of the second resistance connects the connecting node of the third switch and the first capacitor, the other end
Connect the control terminal of the third switch；One end of the 3rd resistor connects the control terminal of the third switch, and the other end connects
Connect the anode of the first diode；The cathode of the first diode connects the output end of the over-current detection module.
In order to achieve the above objects and other related objects, the utility model also provides a kind of power conversion system, the function
Rate transformation system includes at least: the current foldback circuit of power conversion circuit and above-mentioned power switch tube；
The current foldback circuit of the power switch tube is connect with the power switch tube in the power conversion circuit, to work as
When flowing through the overcurrent of the power switch tube in the power conversion circuit, the power switch tube shutdown is controlled, together
When slow down the turn-off speed of power switch tube.
Optionally, the power conversion circuit includes pfc circuit.
Optionally, the pfc circuit includes filter capacitor, reactor, power switch tube, booster diode and smooth electricity
Hold；
The filter capacitor is connected between the input anode of the power inverter and input cathode；
One end of the reactor connects the input anode of the power inverter, and the other end connects the booster diode
Anode, the booster diode cathode connection DC bus-bar voltage output end；
The power switch tube is connected to the anode of the booster diode and with reference between ground, and control terminal connects the drive
Dynamic model block；
The smoothing capacity is connected to the output end of the DC bus-bar voltage and with reference between ground.
Optionally, the sampling module includes the first sampling resistor, first sampling resistor and the power switch tube
Series connection, the over-current detection module receive the voltage on first sampling resistor.
More optionally, the sampling module further includes the second sampling resistor, and one end of second sampling resistor connects institute
The input cathode of power conversion circuit is stated, the other end is connected to reference to ground, detects the input side electric current of the power switch tube, institute
State the control module of the voltage transmission on the second sampling resistor to the power switch tube.
Optionally, the sampling module includes third sampling resistor, and one end of the third sampling resistor connects the function
The input cathode of rate translation circuit, the other end are connected to reference to ground；The over-current detection module receives the third sampling resistor
On voltage.
More optionally, the voltage on the third sampling resistor is also transmitted to the control module of the power switch tube.
As described above, the power conversion system of the utility model and the current foldback circuit of power switch tube, have following
The utility model has the advantages that
The power conversion system of the utility model and the current foldback circuit detection of power switch tube flow through power switch tube
Electric current, and overcurrent protection is executed according to the electric current that detects, and slow down power switch tube while executing overcurrent protection
Turn-off speed avoids the voltage overshoot in the power switch tube, and then improves the stability and safety of power conversion system.
Detailed description of the invention
Fig. 1 is shown as a kind of embodiment schematic diagram of the power conversion system of the utility model.
Fig. 2 is shown as the another embodiment schematic diagram of the power conversion system of the utility model.
Fig. 3 is shown as the another embodiment schematic diagram of the over-current detection module of the utility model.
Fig. 4 is shown as another embodiment schematic diagram of the power conversion system of the utility model.
Fig. 5 is shown as the another embodiment schematic diagram of the power conversion system of the utility model.
Component label instructions
1 power conversion system
11 power conversion circuits
The current foldback circuit of 12 power switch tubes
121 sampling modules
122 over-current detection modules
1221 first over-current detection modules
1222 second over-current detection modules
1223 third over-current detection modules
123 drive modules
124 soft switching protective modules
1241 first soft switching protective modules
1242 second soft switching protective modules
1243 third soft switching protective modules
Specific embodiment
Illustrate the embodiments of the present invention below by way of specific specific example, those skilled in the art can be by this theory
Content disclosed by bright book understands other advantages and effect of the utility model easily.The utility model can also be by addition
Different specific embodiments are embodied or practiced, and the various details in this specification can also be based on different viewpoints and answer
With carrying out various modifications or alterations under the spirit without departing from the utility model.
Please refer to FIG. 1 to FIG. 5.It should be noted that diagram provided in the present embodiment only illustrates this in a schematic way
The basic conception of utility model is only shown with related component in the utility model rather than when according to actual implementation in schema then
Component count, shape and size are drawn, when actual implementation kenel, quantity and the ratio of each component can arbitrarily change for one kind
Become, and its assembly layout kenel may also be increasingly complex.
Embodiment one
As shown in Figure 1, the utility model provides a kind of power conversion system 1, the power conversion system 1 includes:
Power conversion circuit 11 and the current foldback circuit of power switch tube 12.
As shown in Figure 1, the input signal of the power conversion circuit 11 is the absolute value signal of alternating current, being used for will be described
The absolute value signal of alternating current is converted to DC bus-bar voltage.
Specifically, the power conversion circuit 11 includes pfc circuit, such as booster circuit, reduction voltage circuit or lifting piezoelectricity
Road can be set as needed different power conversion architectures, not enumerated and be limited with the present embodiment.As shown in Figure 1, in the present embodiment
In, the power conversion circuit 11 is one of booster circuit, specifically includes filter capacitor C1, reactor L1, power switch
Pipe Q1, booster diode D1 and smoothing capacity C2.The rectification circuit of the input terminal connection alternating current of the power conversion circuit 11
(not shown).
More specifically, the filter capacitor C1 is connected to the input anode Vi+ of the power conversion circuit 11 and input is born
Between the Vi- of pole；One end of the reactor L1 connects the input anode of the power conversion circuit 11, and the other end connects the liter
Press the anode of diode D1, the output end vo of the cathode connection DC bus-bar voltage of the booster diode D1；The power is opened
The collector for closing pipe Q1 connects the anode of the booster diode D1, and emitter connects the sampling module 121, and gate pole connects institute
State drive module 123.The smoothing capacity C2 is connected to the output end vo of the DC bus-bar voltage and with reference between ground PGND.
In the present embodiment, the output end vo of the just extremely described DC bus-bar voltage of the DC bus-bar voltage, the DC bus
The cathode of voltage is described with reference to ground PGND.
It should be noted that in the present embodiment, the power switch tube Q1 is insulated gate bipolar transistor；In reality
The type of the power switch tube Q1 can be set as needed in use, including but not limited to Metal-Oxide Semiconductor field is imitated
Transistor is answered, is adopted described in the anode of the booster diode D1, source electrode connection at this point, the drain electrode of the power switch tube Q1 connects
Egf block 121, grid connect the drive module 123.
It should be noted that in the present embodiment, the smoothing capacity C2 is a capacitor, in actual use, described
Smoothing capacity C2 can be the series and parallel or series-parallel of multiple capacitors, be not limited to this embodiment.
As shown in Figure 1, the current foldback circuit 12 of the power switch tube connects the power conversion circuit 11, when stream
When overcurrent through the power switch tube Q1, the power switch tube Q1 shutdown is controlled, while slowing down the power switch
The turn-off speed of pipe Q1.The current foldback circuit 12 of the power switch tube include sampling module 121, over-current detection module 122,
Drive module 123 and soft switching protective module 124.
Specifically, the sampling module 121 is connect with the power switch tube Q1, flows through the power switch for detecting
The electric current of pipe Q1.
It should be noted that the connection of the sampling module 121 and the power switch tube Q1 include be directly connected to and
It connects in succession, the sampling module 121 can detect the electric current for flowing through the power switch tube Q1.
More specifically, the sampling module 121 includes the first sampling resistor R1.The first sampling resistor R1 and the function
Rate switching tube Q1 series connection, acquisition flow through the electric current of the power switch tube Q1, are the current foldback circuit of the power switch tube
12 provide over-current detection signal, and then realize the hardware overcurrent protection to the power switch tube Q1；In the present embodiment, described
One end of first sampling resistor R1 connects the emitter of the power switch tube Q1, and other end connection is with reference to ground PGND.
It should be noted that in practical applications, the first sampling resistor R1 may connect to the power switch tube Q1
Collector and the booster diode D1 anode between, be not limited to the present embodiment.
It should be noted that in practical applications, the sampling module 121 can also pass through in addition to using sampling resistor
Other modes are realized and are not limited to the present embodiment, such as sensor or mutual inductor are sampled, and will not repeat them here.
Specifically, the over-current detection module 122 connects the output end of the sampling module 121, based on flowing through the function
The electric current output phase of rate switching tube Q1 should cross flow control signals.
More specifically, the over-current detection module 122 is used to be greater than overcurrent in the electric current for flowing through the power switch tube Q1
Output overcurrent controls signal when protecting wealthy value.
It should be noted that the over-current detection module 122 can be hardware over-current detection or software over-current detection.When for
When hardware over-current detection, the over-current detection module 122 is hardware over-current detection circuit, and above-mentioned overcurrent protection threshold value is hardware mistake
Stream protection threshold value；When for software over-current detection, the over-current detection module 122 can pass through the control of the power switch tube Q1
Module realizes that above-mentioned overcurrent protection threshold value is software overcurrent protection threshold value.
In the present embodiment, the over-current detection module 122 is hardware over-current detection circuit.The over-current detection module 122
The input terminal emitter that is connected to the power switch tube Q1 and a reference voltage Vref (reference voltage corresponds to
The above-mentioned wealthy value of hardware overcurrent protection), on the first sampling resistor R1 voltage and the reference voltage Vref be compared,
Flow control signals should be crossed with output phase；In the present embodiment, the over-current detection module 122 includes that comparator CMP and first is opened
Q2 is closed, the normal phase input end of the comparator CMP connects the emitter of the power switch tube Q1, described in inverting input terminal connection
Reference voltage Vref；The grid of the first switch Q2 connects the output end of the comparator CMP, and source electrode ground connection, drain conduct
The output end of the over-current detection module 122.In practical applications, the connection relationship of the input terminal of the comparator CMP can be mutual
It changes, polarity is adjusted to realize identical logic by phase inverter, is not limited to this embodiment.When flowing through the power switch
When the overcurrent of pipe Q1, the first switch Q2 is connected in the comparator CMP output high level, so that the first switch Q2
Drain electrode be pulled low as low level, i.e., output overcurrent controls signal；When the non-overcurrent of the electric current for flowing through the power switch tube Q1,
The comparator CMP exports low level, and first switch Q2 is not turned on, i.e., output overcurrent does not control signal.The first switch Q2
Type include but is not limited to triode, Metal-Oxide Semiconductor field effect transistor, in the present embodiment, described first
Switch Q2 is Metal-Oxide Semiconductor field effect transistor.
It should be noted that the comparator CMP can be integrated in the control module of the power switch tube Q1, pass through institute
State control of the control module realization of power switch tube Q1 to the drive module 123 and the soft switching protective module 124.
In the present embodiment, the comparator CMP is placed outside the control module of the power switch tube Q1, directly controls the driving mould
Block 123 and the soft switching protective module 124, fast response time.
It should be noted that the first switch Q2 can be not provided with, the comparator CMP output level is able to achieve overcurrent
When turn off the power switch tube Q1 and slow down the logic function of the turn-off speed of the power switch tube Q1, not with this reality
Example is applied to be limited.
Specifically, the drive module 123 is connected to the output end of the over-current detection module 122, when flowing through the function
When the overcurrent of rate switching tube Q1, the power switch tube Q1 shutdown is driven based on the corresponding flow control signals of crossing.
More specifically, in the present embodiment, the enable end EN connection over-current detection module of the drive module 123
122 output end (drain electrode of the first switch Q2)；The input terminal IN of the drive module 123 receives the power switch tube
Control the signal PFC_PWM, the control signal PFC_PWM of Q1 derives from the control module of the power switch tube Q1；It is described
The output end OUT of drive module 123 connects the base stage of the power switch tube Q1.The drive module 123 can by chip or
Circuit module is realized, will not repeat them here.When flowing through the overcurrent of the power switch tube Q1, the over-current detection mould
The first switch Q2 is connected in comparator CMP output high level in block 122, and the enable end EN of the drive module 123 is drawn
Low failure, the 123 output end OUT of drive module is without output, then the power switch tube Q1 is turned off；When flowing through the power
When the non-overcurrent of the electric current of switching tube Q1, the comparator CMP in the over-current detection module 122 exports low level, and described first opens
It closes Q2 not turning on, the enable end EN of the drive module 123 is suspended that enabled (enable end is high level or hanging in the present embodiment
Enabled, enable end is that low level then enables failure), the output end OUT of the drive module 123 follows the drive module
123 input terminal IN, and the control signal PFC_PWM is amplified, to drive the power switch tube Q1 to work normally
(on or off).
Specifically, the soft switching protective module 124 is connected to the output end of the over-current detection module 122, when flowing through
When the overcurrent of the power switch tube Q1, based on the corresponding shutdown speed crossed flow control signals and control the power switch tube Q1
Degree, avoids the voltage overshoot on the power switch tube Q1.
More specifically, the soft switching protective module 124 is used for when flowing through the overcurrent of the power switch tube Q1,
Based on the corresponding discharge capacity crossed flow control signals and increase the power switch tube Q1, slow down the power switch tube Q1's with this
Turn-off speed.
In the present embodiment, the soft switching protective module 124 includes third switch Q4, first capacitor C3, first resistor
R3, second resistance R4,3rd resistor R5 and first diode D2.The third switch Q4 and the first capacitor C3 are series at institute
It states the control terminal of power switch tube Q1 and with reference between ground, the control terminal of the third switch Q4 is through the 3rd resistor R5 connection
To the anode of the first diode D2, the cathode of the first diode D2 connects the output of the over-current detection module 122
End.The type of the third switch Q4 includes but is not limited to triode, Metal-Oxide Semiconductor field effect transistor, at this
In embodiment, the third switch Q4 is triode, and the collector of the third switch Q4 connects the power switch tube Q1's
The emitter of base stage, the third switch Q4 is connected to the reference ground PGND via the first capacitor C3, and the third is opened
The base stage for closing Q4 connects the 3rd resistor R5.One end of the first resistor R3 connects the third switch Q4 and described first
The connecting node of capacitor C3, the other end connect a predeterminated voltage V1.One end of the second resistance R4 connects the third switch
The connecting node of Q4 and the first capacitor C3, the other end connect the control terminal of the third switch Q4.When flowing through the power
When the overcurrent of switching tube Q1, the comparator CMP output high level conducting described first in the over-current detection module 122 is opened
Q2 is closed, the control terminal of the third switch Q4 is pulled low, so that the third switch Q4 is connected, so that the first capacitor C3 connects
It is connected between the base stage of the power switch tube Q1 and the reference ground PGND, i.e., the described first capacitor C3 and the power switch
Capacitor Cgs (capacitor Cgs is the capacitor being integrated in inside power switch tube Q1) between the base stage of pipe Q1 and emitter is in parallel, makes
The discharge capacity for obtaining the power switch tube Q1 increases, further such that turn-off time t of the power switch tube Q1 increases, with
This slows down the turn-off speed of the power switch tube Q1, and then reduces overshoot voltage；When the electricity for flowing through the power switch tube Q1
When flowing non-overcurrent, the comparator CMP in the over-current detection module 122 exports low level, and the first switch Q2 is not turned on, institute
The control terminal for stating third switch Q4 is suspended, so that the third switch Q4 is not turned on.
It should be noted that in the present embodiment, the third switch Q4 and the first capacitor C3 are main effector
Part, for realizing soft switching, the first resistor R3~3rd resistor R5 is for controlling size of current, the one or two pole
Pipe D2 is additional component, for assisting main devices to work, without influencing the utility model for controlling current direction
Logic function.The third switch Q4 and first capacitor C3 and the cooperation of the additional component of other forms realize that this is practical new
The logic function of type is also included in the protection scope of the utility model, is not limited to the present embodiment.
The present embodiment also provides a kind of over-current protection method of power switch tube, in the present embodiment, the power switch
The over-current protection method of pipe realizes that the overcurrent of the power switch tube is protected based on the current foldback circuit 12 of the power switch tube
Maintaining method includes:
Detection flows through the electric current of the power switch tube Q1, when the electric current for flowing through the power switch tube Q1 is greater than the set value
When, the power switch tube Q1 shutdown is controlled, meanwhile, slow down the turn-off speed of the power switch tube Q1, avoids the power
Voltage overshoot on switching tube Q1.
Specifically includes the following steps:
1) electric current when acquiring power switch tube Q1 conducting using the first sampling resistor in series via.
Specifically, in the present embodiment, the first sampling resistor R1 is connected to the emitter of the power switch tube Q1.
2) voltage on sampling resistor is compared with reference voltage, to determine to flow through the electricity of the power switch tube Q1
Stream whether overcurrent.
3) when flowing through the overcurrent of the power switch tube Q1, the power switch tube Q1 shutdown is controlled.
Specifically, when flowing through the overcurrent of the power switch tube Q1, the over-current detection module 122 controls described
The enable end of drive module 123 is failed, and the drive module 123 is exported without signal, the power switch tube Q1 shutdown.
4) simultaneously, slow down the turn-off speed of the power switch tube Q1, when to avoid power switch tube Q1 shutdown
Voltage overshoot.
Specifically, according to formulaIt is found that between the collector and emitter of the power switch tube Q1
Voltage UceIt is directly proportional to stray inductance L, variation with time directly proportional to the variable quantity di of electric current on the power switch tube Q1
Amount dt is inversely proportional, therefore, when the overcurrent for flowing through the power switch tube Q1 is turned off, the first capacitor C3 and institute
The capacitor Cgs stated inside power switch tube Q1 is in parallel, so that the discharge capacity of the power switch tube Q1 increases, further such that
Turn-off time t of the power switch tube Q1 increases, and the variable quantity dt of time is also increased accordingly, that is, slows down the power switch
The turn-off speed of pipe Q1, so that the voltage U between the collector and emitter of the power switch tube Q1ceIt is corresponding to reduce,
And then voltage overshoot is avoided, protect device.
It should be noted that arbitrarily the power switch tube of the utility model can be used in the system with power switch tube
Over-current protection method is not limited to the present embodiment cited circuit structure.
Embodiment two
As shown in Fig. 2, the present embodiment provides a kind of power conversion system, with embodiment one the difference is that, it is described
The current foldback circuit 12 of power switch tube further includes the second acquisition resistance R2, and the over-current detection module and the soft switching
Protective module includes two.
Specifically, one end of the second sampling resistor R2 connects the input cathode Vi- of the power conversion circuit 11, separately
One end is connected to reference the ground PGND, the second sampling resistor R2 and detects the input side electric current of the power switch tube Q1,
The second sampling resistor R2 connects the control module (not shown) of the power switch tube Q1, and the control module includes
But it is not limited to micro-control unit (Microcontroller Unit；MCU), the control module is based on second sampling resistor
The collected electric current of R2 carries out the pulse width that closed-loop control adjusts the control signal of the power switch tube Q1, and realizes software
Overcurrent protection.
It should be noted that in the present embodiment, the second sampling resistor R2 is protected for closed-loop control and software overcurrent
Shield, removing the second sampling resistor R2 does not influence the current foldback circuit work of the present embodiment.
Specifically, the input terminal of the first over-current detection module 1221 is separately connected the ginseng of the first sampling resistor R1 and first
Voltage Vref1 is examined, the first output end OUT1 connects the enable end EN of the drive module 123, second output terminal OUT2 connection
The input terminal of one soft switching protective module 1241.As shown in figure 3, the first over-current detection module 1221 include comparator CMP,
One end (IN) of first switch Q2 and second switch Q3, the comparator CMP connect the output end of the sampling module 121, separately
One end connects first reference voltage Vref 1, and the output end of the comparator CMP connects the first switch Q2 and described the
The control terminal of two switch Q3；One end connection of the first switch Q2 is described with reference to ground PGND, and the other end is examined as the overcurrent
Survey the first output end OUT1 of module 122；One end connection of the second switch Q3 is described with reference to ground PGND, and the other end is as institute
State the second output terminal OUT2 of over-current detection module 122.When the voltage on the first sampling resistor R1 is greater than first ginseng
When examining voltage Vref1, the signal of the first output end OUT1 of the first over-current detection module 1221 controls the drive module
123 enable end failure, the drive module 123 do not export, and the drive module 123 closes the power switch tube Q1
It is disconnected；Meanwhile the signal of the second output terminal OUT2 of the first over-current detection module 1221 controls the first soft switching protection
Module 1241 works, and determines the power switch tube based on the parameter of 1241 internal components of the first soft switching protective module
The turn-off speed of Q1.
It should be noted that it can also be not provided with the first switch Q2 and second switch Q3 in practical applications,
As long as can be realized logic function, it is not limited to this embodiment.When flowing through the overcurrent of the power switch tube Q1,
The first switch Q2 and second switch Q3 is connected in the comparator CMP output high level, so that the first switch Q2
And the drain electrode of the second switch Q3 is pulled low as low level；When the non-overcurrent of the electric current for flowing through the power switch tube Q1,
The comparator CMP exports low level, and the first switch Q2 and the second switch Q3 are not turned on.The first switch Q2 and
The type of the second switch Q3 includes but is not limited to triode, Metal-Oxide Semiconductor field effect transistor, in this implementation
In example, the first switch Q2 and the second switch Q3 are Metal-Oxide Semiconductor field effect transistor.
Specifically, the input terminal of the second over-current detection module 1222 is separately connected the ginseng of the first sampling resistor R1 and second
Examine voltage Vref2, it is soft that the first output end connects the enable end EN of the drive module 123, second output terminal connection described second
Turn off the input terminal of protective module 1242.The structure and the first over-current detection module of the second over-current detection module 1222
1221 structure is identical, will not repeat them here.When the voltage on the first sampling resistor R1 is greater than described second with reference to electricity
When pressing Vref2, the signal of the first output end OUT1 of the second over-current detection module 1222 controls the drive module 123
Enable end EN failure, makes the drive module 123 without output, the power switch tube Q1 is turned off；Meanwhile second overcurrent
The signal of the second output terminal OUT2 of detection module 1222 controls the second soft switching protective module 1242 and works, and is based on institute
The parameter for stating 1242 internal components of the second soft switching protective module determines the turn-off speed of the power switch tube Q1.
It should be noted that the quantity of over-current detection module can be set as needed, different over-current detection module settings
Different overcurrent protection grade, wherein different reference voltages controls different over current value, different device parameters (described first
The capacitance of capacitor C3) control the different turn-off speed of the power switch tube Q1.The first soft switching protective module 1241 and
The parameter of device can be set as needed in the second soft switching protective module 1242, be connected to the power switch tube Q1's
Control terminal and the size with reference to the capacitor between ground PGND influence the turn-off speed of the power switch tube Q1.
The over-current protection method of the power switch tube of the present embodiment is adjusted by disparate modules on the basis of example 1
The turn-off speed of power switch tube specifically adjusts the power according to the over current value for flowing through the power switch tube Q1 and opens
The turn-off speed of pipe Q1 is closed, the turn-off speed of the over current value and the power switch tube Q1 that flow through the power switch tube Q1 is in
Inverse ratio；That is, the over current value for flowing through the power switch tube Q1 is bigger, the control terminal of the power switch tube Q1 is accessed
It is described bigger with reference to the capacitor between ground PGND, occurrence according to system parameter and can be set, herein not one by one
It repeats.
Embodiment three
As shown in figure 4, the present embodiment provides a kind of power conversion system, with embodiment two the difference is that, it is described
The current foldback circuit 12 of power switch tube does not include the second acquisition resistance R2, and the over-current detection module and the soft switching are protected
Protecting module includes three, and the output signal of each over-current detection module controls the input terminal of the drive module 123, output respectively
End and enable end.
Specifically, the first output end of the first over-current detection module 1221 connects the input terminal of the drive module 123,
Two output ends connect the input terminal of the first soft switching protective module 1241.First output end of the second over-current detection module 1222 connects
Connect the enable end of the drive module 123, the input terminal of second output terminal the second soft switching protective module 1242 of connection.Third mistake
First output end of stream detection module 1223 connects the output end of the drive module 123, the second output terminal connection soft pass of third
The input terminal of disconnected protective module 1243.It is turned off respectively by dragging down input terminal, enable end or the output end of the drive module 123
The power switch tube Q1.
It should be noted that each over-current detection module and 123 input, output end of drive module and enabled end switch
Corresponding relationship can adjust as needed, be not limited to this embodiment.And the quantity of over-current detection module can be set as needed,
The output end of each over-current detection module is connected at least one end in the drive module enable end, input terminal or output end, no
It is limited with the present embodiment.Wherein, the response speed for dragging down input terminal is higher than the response speed of invalid enable end, drags down output end
Response speed is higher than the response speed for dragging down input terminal, and the present embodiment is greatly improved response speed compared to software overcurrent protection
Degree.
It should be noted that the first soft switching protective module 1241, the second soft switching protective module 1242 and
The parameter of device can be set as needed in the third soft switching protective module 1243, be connected to the power switch tube Q1's
Control terminal and the size with reference to the capacitor between ground PGND influence the turn-off speed of the power switch tube Q1.
Example IV
As shown in figure 5, the present embodiment provides a kind of power conversion system 1, with embodiment one the difference is that, this reality
Example is applied using third sampling resistor R3 as the sampling module 121；And the current foldback circuit 12 of the power switch tube is also
Including the 4th resistance R6, the 5th resistance R7, the second diode D3 and third diode D4.
Specifically, one end of the third sampling resistor R3 connects the input cathode Vi- of the power conversion circuit 11, separately
One end is connected to described with reference to ground PGND.Voltage on the third sampling resistor R3 is supplied to the over-current detection module 122
And the control module (not shown) of the power switch tube Q1.
More specifically, the third sampling resistor R3 acquires the input side electric current of the detection power switch tube Q1；
When power switch tube Q1 conducting, the electric current that the third sampling resistor R3 is detected is to flow through the power switch tube Q1
Electric current, when the power switch tube Q1 overcurrent, the voltage on the third sampling resistor R3 promotes the over-current detection mould
The output end of block 122 jumps.When power switch tube Q1 shutdown, the electric current that the third sampling resistor R3 is detected is stream
The electric current of the reactor L1 is crossed, the control module of the power switch tube Q1 is read on the third sampling resistor R3 at this time
Voltage, and the pulse width for adjusting the control signal PFC_PWM accordingly realizes closed-loop control, meanwhile, accordingly by the control
Signal PFC_PWM processed executes software overcurrent protection.
It can detecte it should be noted that the present embodiment is based on the third sampling resistor R3 due to the reactor L1
The problem of current over pulse of the power switch tube Q1 is flowed through caused by failure.And embodiment one had been based on the first sampling resistor R1 both
The problem of flowing through the current over pulse of the power switch tube Q1 as caused by the reactor L1 failure can be detected, and can examine
The problem of measuring the current over pulse that the power switch tube Q1 is flowed through as caused by the booster diode D1 failure, can be more
Mend the overcurrent that can not detect of third sampling resistor R3, the safer and more effective protection device for power switching, circuit can
It is higher by property, it is more rigorous and comprehensive.
Specifically, one end of the 4th resistance R6 connects the control terminal of the power switch tube Q1, and the other end connects institute
The anode of the second diode D3 is stated, the cathode of the second diode D3 connects the output end of the drive module 123；Described
One end of five resistance R7 connects the control terminal of the power switch tube Q1, and the other end connects the cathode of the third diode D4,
The anode of the third diode D4 connects the output end of the drive module 123.
It should be noted that in the present embodiment, the 4th resistance R6~the 5th resistance R7 is for controlling electric current
Size, the second diode D3~third diode D4 are additional component, lead for assisting for controlling current direction
Device is wanted to work, the logic function without influencing the utility model.The utility model further includes some other additional components,
Be used to assist each functional module to work, those skilled in the art are known, will not repeat them here, thus main devices and its
He realizes that the logic function of the utility model is also included in the protection scope of the utility model at additional component cooperation.
In conclusion the utility model provides the current foldback circuit of a kind of power conversion system and power switch tube, packet
Include: sampling module is connect with power switch tube, and detection flows through the electric current of the power switch tube；An at least over-current detection module,
The output end for connecting the sampling module should cross flow control signals based on the electric current output phase for flowing through the power switch tube；It drives
Dynamic model block is connected to the output end of the over-current detection module, when flowing through the overcurrent of the power switch tube, drives institute
State power switch tube shutdown；Soft switching protective module is corresponded with the over-current detection module, is connected to each overcurrent inspection
The output end for surveying module is crossed described in flow control signals control when flowing through the overcurrent of the power switch tube based on corresponding
The turn-off speed of power switch tube avoids the voltage overshoot in the power switch tube.Detection flows through the electric current of power switch tube,
When the electric current for flowing through the power switch tube is greater than the set value, the power switch tube shutdown is controlled, meanwhile, slow down the function
The turn-off speed of rate switching tube avoids the voltage overshoot in the power switch tube.The power conversion system of the utility model and
The current foldback circuit detection of power switch tube flows through the electric current of power switch tube, and executes overcurrent according to the electric current detected and protect
Shield, and the turn-off speed for slowing down power switch tube while overcurrent protection is being executed, avoid the voltage in the power switch tube
Overshoot, and then improve the stability and safety of power conversion system.So the utility model effectively overcomes in the prior art
Various shortcoming and have high industrial utilization value.
The above embodiments are only illustrative of the principle and efficacy of the utility model, and not for limitation, this is practical new
Type.Any person skilled in the art can all carry out above-described embodiment under the spirit and scope without prejudice to the utility model
Modifications and changes.Therefore, such as those of ordinary skill in the art without departing from the revealed essence of the utility model
All equivalent modifications or change completed under mind and technical idea, should be covered by the claim of the utility model.
Claims (14)
1. a kind of current foldback circuit of power switch tube, which is characterized in that the current foldback circuit of the power switch tube is extremely
Include: less
Sampling module is connect with power switch tube, and detection flows through the electric current of the power switch tube；
An at least over-current detection module, connects the output end of the sampling module, based on the electric current for flowing through the power switch tube
Output phase should cross flow control signals；
Drive module is connected to the output end of the over-current detection module, when flowing through the overcurrent of the power switch tube,
The power switch tube shutdown is driven based on the corresponding flow control signals of crossing；
An at least soft switching protective module corresponds with the over-current detection module, is connected to each over-current detection module
Output end, when flowing through the overcurrent of the power switch tube, based on it is corresponding cross flow control signals and control the power open
The turn-off speed for closing pipe, avoids the voltage overshoot in the power switch tube.
2. the current foldback circuit of power switch tube according to claim 1, it is characterised in that: the power switch tube packet
Include insulated gate bipolar transistor.
3. the current foldback circuit of power switch tube according to claim 1, it is characterised in that: the over-current detection module
Including comparator and first switch；
The input terminal of the comparator is separately connected the sampling module and a reference voltage, the output end connection of the comparator
The control terminal of the first switch；One end connection of the first switch is with reference to ground, and the other end is as the over-current detection module
Output end；The output end of the sampling module is compared by the comparator with the reference voltage, and controls described
One switch output phase should cross flow control signals.
4. the current foldback circuit of power switch tube according to claim 3, it is characterised in that: the over-current detection module
It further include second switch；
The output end of the comparator connects the control terminal of the first switch and the second switch；The one of the first switch
End connection is with reference to ground, first output end of the other end as the over-current detection module；One end of the second switch connects ginseng
Examine ground, second output terminal of the other end as the over-current detection module；First output end of the over-current detection module and
Two output ends are separately connected the drive module and the soft switching protective module.
5. the current foldback circuit of power switch tube according to claim 1, it is characterised in that: the soft switching protects mould
Block receives the mistake flow control signals of the over-current detection module output, for when the overcurrent for flowing through the power switch tube
When, based on the corresponding discharge capacity crossed flow control signals and increase the power switch tube, the power switch tube is slowed down with this
Turn-off speed.
6. the current foldback circuit of power switch tube according to claim 5, it is characterised in that: the soft switching protects mould
Block includes third switch and first capacitor；
Third switch and the first capacitor are series at the control terminal of the power switch tube and with reference between ground, and described the
The control terminal of three switches connects the output end of the over-current detection module.
7. the current foldback circuit of power switch tube according to claim 6, it is characterised in that: the soft switching protects mould
Block further includes first resistor, second resistance, 3rd resistor and first diode；
One end of the first resistor connects the connecting node of the third switch and the first capacitor, and other end connection one is pre-
If voltage；One end of the second resistance connects the connecting node of the third switch and the first capacitor, other end connection
The control terminal of the third switch；One end of the 3rd resistor connects the control terminal of the third switch, and the other end connects institute
State the anode of first diode；The cathode of the first diode connects the output end of the over-current detection module.
8. a kind of power conversion system, which is characterized in that the power conversion system includes at least: power conversion circuit and such as
The current foldback circuit of power switch tube described in claim 1~7 any one；
The current foldback circuit of the power switch tube is connect with the power switch tube in the power conversion circuit, is flowed through with working as
When the overcurrent of the power switch tube in the power conversion circuit, the power switch tube shutdown is controlled, is subtracted simultaneously
The turn-off speed of slow power switch tube.
9. power conversion system according to claim 8, it is characterised in that: the power conversion circuit includes pfc circuit.
10. power conversion system according to claim 9, it is characterised in that: the pfc circuit includes filter capacitor, electricity
Anti- device, power switch tube, booster diode and smoothing capacity；
The filter capacitor is connected between the input anode of the power conversion circuit and input cathode；
One end of the reactor connects the input anode of the power conversion circuit, and the other end connects the booster diode
Anode, the output end of the cathode connection DC bus-bar voltage of the booster diode；
The power switch tube is connected to the anode of the booster diode and with reference between ground, and control terminal connects the driving mould
Block；
The smoothing capacity is connected to the output end of the DC bus-bar voltage and with reference between ground.
11. according to power conversion system described in claim 8~10 any one, it is characterised in that: the sampling module packet
The first sampling resistor is included, first sampling resistor is connected with the power switch tube, described in the over-current detection module reception
Voltage on first sampling resistor.
12. power conversion system according to claim 11, it is characterised in that: the sampling module further includes the second sampling
Resistance, one end of second sampling resistor connect the input cathode of the power conversion circuit, and the other end is connected to reference to ground,
The input side electric current of the power switch tube is detected, the voltage transmission on second sampling resistor to the power switch tube
Control module.
13. according to power conversion system described in claim 8~10 any one, it is characterised in that: the sampling module packet
Third sampling resistor is included, one end of the third sampling resistor connects the input cathode of the power conversion circuit, and the other end connects
It is connected to reference to ground；The over-current detection module receives the voltage on the third sampling resistor.
14. power conversion system according to claim 13, it is characterised in that: the voltage on the third sampling resistor is also
It is transmitted to the control module of the power switch tube.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821609862.4U CN209016697U (en) | 2018-09-30 | 2018-09-30 | The current foldback circuit of power conversion system and power switch tube |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821609862.4U CN209016697U (en) | 2018-09-30 | 2018-09-30 | The current foldback circuit of power conversion system and power switch tube |
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| Publication Number | Publication Date |
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| CN209016697U true CN209016697U (en) | 2019-06-21 |
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ID=66835011
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| CN201821609862.4U Active CN209016697U (en) | 2018-09-30 | 2018-09-30 | The current foldback circuit of power conversion system and power switch tube |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109245055A (en) * | 2018-09-30 | 2019-01-18 | 浙江鲲悟科技有限公司 | Power conversion system, the current foldback circuit of power switch tube and method |
| CN111901923A (en) * | 2020-08-03 | 2020-11-06 | 四川遂宁市利普芯微电子有限公司 | Overcurrent protection circuit of common-cathode LED display line driving chip |
| CN112202388A (en) * | 2020-09-27 | 2021-01-08 | 台安科技(无锡)有限公司 | Multistage series H bridge power unit protection device of high-voltage frequency converter |
| WO2023197594A1 (en) * | 2022-04-11 | 2023-10-19 | 潍柴动力股份有限公司 | Overvoltage protection driving circuit, motor driving circuit, and vehicle |
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2018
- 2018-09-30 CN CN201821609862.4U patent/CN209016697U/en active Active
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109245055A (en) * | 2018-09-30 | 2019-01-18 | 浙江鲲悟科技有限公司 | Power conversion system, the current foldback circuit of power switch tube and method |
| CN109245055B (en) * | 2018-09-30 | 2024-05-31 | 上海鲲悟丰电科技有限公司 | Power conversion system, overcurrent protection circuit and method of power switch tube |
| CN111901923A (en) * | 2020-08-03 | 2020-11-06 | 四川遂宁市利普芯微电子有限公司 | Overcurrent protection circuit of common-cathode LED display line driving chip |
| CN111901923B (en) * | 2020-08-03 | 2023-10-03 | 四川遂宁市利普芯微电子有限公司 | Overcurrent protection circuit of common-cathode LED display line driving chip |
| CN112202388A (en) * | 2020-09-27 | 2021-01-08 | 台安科技(无锡)有限公司 | Multistage series H bridge power unit protection device of high-voltage frequency converter |
| WO2023197594A1 (en) * | 2022-04-11 | 2023-10-19 | 潍柴动力股份有限公司 | Overvoltage protection driving circuit, motor driving circuit, and vehicle |
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