CN113131743B - Isolated power supply and secondary side control circuit thereof - Google Patents
Isolated power supply and secondary side control circuit thereof Download PDFInfo
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- CN113131743B CN113131743B CN201911413855.6A CN201911413855A CN113131743B CN 113131743 B CN113131743 B CN 113131743B CN 201911413855 A CN201911413855 A CN 201911413855A CN 113131743 B CN113131743 B CN 113131743B
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- heat dissipation
- control circuit
- power supply
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
Abstract
An isolated power supply and a secondary side control circuit thereof. The isolated power supply comprises: a transformer; a primary side switch for switching the primary side winding to convert an input power into an output power; the primary side driving circuit generates a switching signal according to the feedback signal to operate the primary side switch; the secondary side control circuit generates a feedback signal according to the output power supply; the feedback signal transmission circuit is coupled between the primary side drive circuit and the secondary side control circuit and transfers the feedback signal to the primary side drive circuit in a non-contact induction mode; the secondary side control circuit comprises a heat dissipation control circuit, and generates a heat dissipation control signal according to the output power supply and the input power supply so as to control the heat dissipation fan. In addition, the isolated power supply can further comprise an alarm processing unit which correspondingly generates an alarm control signal according to the input power supply, the output power supply and the heat dissipation control signal.
Description
Technical Field
The present invention relates to an isolated power supply, and more particularly to an isolated power supply for controlling a heat dissipation fan according to an output power and an input power. The invention also relates to a secondary side control circuit used in the isolated power supply.
Background
Fig. 1 shows a schematic diagram of a control circuit of a heat dissipation fan in the prior art. As shown in fig. 1, the control circuit 10 of the heat dissipation fan 1 switches the switch SW1 according to the activation signal Str to determine whether to electrically connect to the supply voltage VCC. When the heat dissipation fan 1 is electrically connected to the supply voltage VCC, it starts to rotate, thereby enabling the heat dissipation function. That is, when switch SW1 is turned on by activation signal Str, heat dissipation fan 1 rotates to start dissipating heat. The prior art heat dissipation fan control circuit 10 shown in fig. 1 can be applied to various circuits. The advantage of the control circuit 10 of the heat dissipation fan in the prior art is that heat dissipation is performed continuously as soon as the circuit is turned on (conducting), and the heat dissipation effect is optimal. That is, the starting signal Str is coupled to the applied circuit, and once the applied circuit is started, the heat dissipation fan 1 keeps rotating continuously to dissipate heat. This has the disadvantage that the heat dissipation fan 1 is kept rotating even when heat dissipation is not required, which wastes electric power and causes noise.
FIG. 2 is a schematic diagram of another prior art heat dissipation fan control circuit. As shown in fig. 2, the control circuit 20 of the heat dissipation fan 1 determines to turn on or turn off the switch SW2 therein according to the thermosensitive signal Stm, and determines whether to turn on the circuit electrically connecting the heat dissipation fan 1 between the supply voltage VCC and the ground potential GND, so as to operate or not operate the heat dissipation fan 1. The thermosensitive signal Stm is determined according to a resistance value of the thermistor TM, that is, a temperature around the thermistor TM changes the resistance value of the thermistor TM, and the thermosensitive signal Stm is determined to enable or disable the heat dissipation function. As shown in fig. 2, the thermistor TM is connected in series to the voltage dividing circuit 201 in the control circuit 20, when the temperature around the thermistor TM changes the resistance of the thermistor TM, the voltage level of the thermosensitive signal Stm also changes accordingly, and when the voltage level of the thermosensitive signal Stm exceeds the threshold voltage of the switch SW2, taking the switch SW2 in the control circuit 20 as an example, a NPN Bipolar Junction Transistor (BJT), that is, when the voltage level of the thermosensitive signal Stm makes the base-emitter of the NPNBJT forward conductive and operate in a saturation region, the cooling fan 1 starts to operate, and the cooling function is enabled.
The control circuit 20 of the heat dissipation fan 1 of the prior art can solve the disadvantages of the control circuit 10 of the prior art shown in fig. 1, that is, the heat dissipation function is enabled only when the thermistor TM senses the temperature rise around the thermistor TM, so as to avoid the waste of electric energy. However, fig. 2 shows that the control circuit 20 of the heat dissipation fan 1 in the prior art has a disadvantage that the thermistor TM can only sense the ambient temperature around itself, and often cannot represent the area actually requiring the heat dissipation function, in this case, the heat dissipation time is delayed, which may affect the electrical characteristics of the circuit elements or damage the circuit elements.
Therefore, the present invention provides an isolated power supply capable of controlling a heat dissipation fan according to an output power and an input power. The invention also relates to a secondary side control circuit used in the isolated power supply.
Disclosure of Invention
From one aspect, the present invention provides an isolated power supply, comprising: a transformer including a primary winding and a secondary winding coupled to each other by electromagnetic induction (electromagnetic induction), wherein the primary winding is electrically coupled to an input power source; a primary side switch coupled to the primary side winding for switching the primary side winding to convert the input power into an output power from the secondary side winding; a primary side driving circuit coupled to the primary side switch for generating a switching signal according to a feedback signal to operate the primary side switch; a secondary side control circuit for generating the feedback signal according to the output power; and a feedback signal transmission circuit, coupled between the primary side drive circuit and the secondary side control circuit, for transferring the feedback signal to the primary side drive circuit in a non-contact induction manner; the secondary side control circuit comprises a heat dissipation control circuit used for generating a heat dissipation control signal according to an output power supply and the input power supply so as to control a heat dissipation fan.
From another perspective, the present invention also provides a secondary control circuit for use in an isolated power supply, the secondary control circuit comprising: a feedback signal processing unit for generating a feedback signal according to an output power; and a heat dissipation control circuit, which is used for generating a heat dissipation control signal according to the output power supply and an input power supply so as to control a heat dissipation fan; the feedback signal is transferred to the primary side drive circuit in a non-contact induction mode through a feedback signal transmission circuit coupled between a primary side drive circuit and the secondary side control circuit; the primary side driving circuit generates a switching signal according to the feedback signal to operate a primary side switch; the primary side switch is used for switching a primary side winding of a transformer according to the switching signal so as to convert the input power supply into the output power supply through the transformer by electromagnetic induction, wherein the output power supply is provided with a secondary side winding of the transformer.
In a preferred embodiment, the isolated power supply further includes an output sampling circuit coupled to the secondary winding for generating an output sampling signal related to the output power according to an output current flowing through the secondary winding, and the heat dissipation control circuit generates the heat dissipation control signal according to the output sampling signal.
In a preferred embodiment, the secondary side control circuit further comprises an output signal processing unit for generating an output power related signal according to the output sampling signal to be input to the heat dissipation control circuit.
In a preferred embodiment, the isolated power supply further includes an input signal transmission circuit coupled between the primary-side switch and the secondary-side control circuit, for transmitting an input power related signal related to the switching current to the secondary-side control circuit in a non-contact induction manner according to a switching current flowing through the primary-side switch, so that the heat dissipation control circuit generates the heat dissipation control signal according to the input power related signal.
In a preferred embodiment, the feedback signal transmission circuit includes a feedback transformer, and the heat dissipation control circuit generates the heat dissipation control signal according to a tap voltage of a feedback secondary winding in the feedback transformer.
In the aforementioned embodiment, the heat dissipation control circuit includes a feedback tap amplifying circuit coupled to the feedback secondary winding for generating the heat dissipation control signal according to the tap voltage and a reference voltage.
In a preferred embodiment, the isolated power supply further comprises a temperature sensing device coupled to the heat dissipation fan for generating a temperature sensing signal according to an ambient temperature to control the heat dissipation fan.
In a preferred embodiment, the primary side switch includes an upper bridge switch and a lower bridge switch, which respectively receive an upper bridge switching signal and a lower bridge switching signal of the switching signal to switch the primary side winding, wherein the upper bridge switch and the lower bridge switch are not turned on simultaneously.
In a preferred embodiment, the secondary side control circuit further includes a feedback signal processing unit for generating the feedback signal according to the output power.
In a preferred embodiment, the secondary side control circuit further includes an alarm processing unit for generating an input power alarm signal, an output power alarm signal, and a temperature alarm signal according to the input power, the output power, and the heat dissipation control signal.
In a preferred embodiment, the warning processing unit further generates an under-voltage warning signal or an over-voltage warning signal according to whether an output voltage is higher than an upper limit of the output voltage or lower than a lower limit of the output voltage.
The purpose, technical content, features and effects of the present invention will be more readily understood through the following detailed description of specific embodiments.
Drawings
FIG. 1 shows a schematic diagram of a control circuit of a heat dissipation fan in the prior art.
FIG. 2 is a schematic diagram of another prior art heat dissipation fan control circuit.
Fig. 3 shows a first embodiment according to the invention.
Fig. 4 shows a second embodiment according to the invention.
Fig. 5 shows a third embodiment according to the invention.
Fig. 6 shows a fourth embodiment according to the invention.
Fig. 7 shows a fifth embodiment according to the invention.
Fig. 8 shows a sixth embodiment according to the invention.
Fig. 9 shows a seventh embodiment according to the invention.
Description of the symbols in the drawings
1 Heat radiation fan
10,20 control circuit
100,200 isolated power supply
101,201 AC rectifying and filtering unit
102,202 transformer
103,203 Primary side switch
104,204 primary side drive circuit
105,205 secondary side control circuit
106,206 load circuit
107,207 feedback signal transmission circuit
108,208 current sensing circuit
109,209 output sampling circuit
110,210 temperature sensing device
111,211 input signal transmission circuit
112,212 secondary side rectifying and filtering unit
1051,2051 feedback signal processing unit
1052,2052 heat dissipation control circuit
2053 output Signal processing Unit
2054 input Signal processing Unit
2055 Warning processing Unit
AM1 feedback tap amplifying circuit
AM2 output sampling amplifying circuit
C filter capacitor
CS Current sense Signal
ERRRS, ERRRL, ERRTEMP, ERRUVP, ERROVP warning display signal
GATE switching signal
GND ground potential
IDL load current
Iout output current
LG lower bridge switch
LGATE down-bridge switching signal
N21, N22 node
R, RS1 resistance
REF reference potential
Sfb feedback signal
Shd heat dissipation control signal
Sop output sampling signal
Stm thermosensitive signal
Str Start Signal
SW1, SW2 switch
TM thermistor
UG upper bridge switch
UGATE upper bridge switching signal
Vac AC voltage
VCC supply voltage
Vin input voltage
Vfb coupled feedback signal
Vout output voltage
Vr output sampling voltage difference
Vrl2, Vs2 output power-related signals
Vrs1, Vrs3 input power-related signals
Vrs2 coupling input signals
Vref reference voltage
Vs tap voltage
W1 primary winding
W2 Secondary winding
W3 feedback secondary side winding
Detailed Description
The drawings are schematic and are intended to show the coupling relationship between circuits, and the circuits and elements are not drawn to scale.
Fig. 3 shows a first embodiment according to the invention. Referring to fig. 3, a schematic diagram of an isolated power supply 100 according to an embodiment of the invention is shown. The isolated power supply 100 includes an AC rectifying and filtering unit 101, a transformer 102, a primary switch 103, a primary driving circuit 104, a secondary control circuit 105, a feedback signal transmission circuit 107, a current sensing circuit 108, an output sampling circuit 109, an input signal transmission circuit 111, and a secondary rectifying and filtering unit 112.
The AC voltage Vac is rectified by the AC rectifying/smoothing unit 101 to generate an input voltage Vin. The AC rectifying and filtering unit 101 is, for example, but not limited to, a bridge type AC rectifying and filtering unit. In the isolated power supply 100, the transformer 102 includes a primary winding W1 and a secondary winding W2 coupled to each other by electromagnetic induction (electromagnetic induction). The primary winding W1 is coupled to receive an input power having an input voltage Vin.
The primary switch 103 is coupled to the primary winding W1 for switching the primary winding W1 to control the on-time of the primary winding W1, so as to generate an output power having an output voltage Vout between a node N21 and a node N22 of the secondary winding W2 (the node N22 is electrically connected to the ground potential GND), and provide a load current IDL to a load circuit 106 coupled to the output voltage Vout. In the present embodiment, the primary-side switch 103 includes, for example but not limited to, an upper-bridge switch UG and a lower-bridge switch LG, and the upper-bridge switch UGATE and the lower-bridge switch LGATE receive the switching signal GATE and the lower-bridge switching signal LGATE respectively to switch the primary-side winding W1, wherein the upper-bridge switch UG and the lower-bridge switch LG are not turned on simultaneously.
The primary-side driving circuit 104 is located at the primary side of the transformer 102, and is configured to generate a switching signal GATE according to a coupling feedback signal Vfb generated by the feedback signal Sfb to operate the primary-side switch 103, so as to convert the input voltage Vin into the output voltage Vout.
The secondary side rectifying and filtering unit 112 receives the signal generated by the secondary side winding W2, rectifies and filters the signal to generate an output signal, and inputs the output signal to the output sampling circuit 109 through the filter capacitor C as shown in fig. 3 to generate an output voltage Vout and a load current IDL flowing through the load circuit 106.
The secondary control circuit 105 is located on the secondary side of the transformer 102, and includes a feedback signal processing unit 1051 and a heat dissipation control circuit 1052. The feedback signal processing unit 1051 receives the output sampling signal Sop associated with the output power source to generate the feedback signal Sfb.
The feedback signal transmitting circuit 107 is coupled between the primary side driving circuit 104 and the secondary side control circuit 105, and converts the feedback signal Sfb into the coupling feedback signal Vfb in a non-contact induction manner, such as but not limited to an electromagnetic induction manner of a transformer as shown in fig. 3, for inputting to the primary side driving circuit 104. In the present embodiment, the feedback signal transmission circuit 107 is, for example, but not limited to, a transformer as shown in fig. 3.
The heat dissipation control circuit 1052 is used for generating a heat dissipation control signal Shd according to the input power and the output power to control the heat dissipation fan 1. In the present embodiment, the heat dissipation control circuit 1052 generates the heat dissipation control signal Shd according to, for example, the output sampling signal Sop of the output power related signal and the coupling input signal Vrs2 of the input power related signal.
The current sensing circuit 108 is disposed on the primary side of the transformer 102 and connected in series with the primary-side switch 103 for generating an input power-related signal Vrs1 according to a switching current flowing through the primary-side switch 103. In the embodiment, the current sensing circuit 108 includes, for example, a resistor RS1 connected in series with the primary-side switch 103, and a voltage drop generated by a resistor RS1 as the input power related signal Vrs1 is generated by a switching current flowing through the primary-side switch 103 and also flowing through a resistor RS 1.
The output sampling circuit 109 is coupled to the secondary winding W2 for generating an output sampling signal Sop related to the output power according to the output current flowing through the secondary winding W2, and the heat dissipation control circuit 1052 generates the heat dissipation control signal Shd according to the output sampling signal Sop.
The input signal transmitting circuit 111 is coupled between the primary switch 103 and the secondary control circuit 105, and is configured to convert an input power related signal Vrs1 related to a switching current into a coupled input signal Vrs2 in a non-contact sensing manner according to the switching current flowing through the primary switch 103, and transmit the coupled input signal Vrs2 to the secondary control circuit 105, so that the heat dissipation control circuit 1052 generates a heat dissipation control signal Shd according to the input power related signal Vrs 1.
One of the technical features of the present invention over the prior art is that in the present invention, when a parameter related to the output power exceeds a preset output power threshold, for example, but not limited to, the output voltage Vout exceeds a preset output voltage threshold; and a parameter associated with the input power source also exceeds a predetermined input power threshold, such as but not limited to the input voltage Vin exceeding a predetermined input voltage threshold, or the coupling input signal Vrs2 exceeding a predetermined coupling input signal threshold; according to the present invention, the heat dissipation control signal Shd can be adjusted/changed to enable or disable the heat dissipation function, and to turn on or off the heat dissipation fan 1; and further, the rotation speed of the heat dissipation fan 1 can be adjusted by the heat dissipation control signal Shd. Compared with the prior art, the invention can utilize the output power supply and the relevant parameters of the output power supply to determine whether to enable or disable the heat dissipation function, and can also adjust the rotating speed of the heat dissipation fan 1, thereby improving the defects that the prior art wastes electric energy or the thermistor cannot represent the area really needing the heat dissipation function, and further accurately controlling the heat dissipation condition.
In detail, the present invention provides an isolated power supply and a secondary side control circuit thereof, which utilize a heat dissipation control circuit 1052 to start to control the rotation of a heat dissipation fan 1 in advance just before the temperature of the working environment rises, so as to avoid the life and characteristic distortion of circuit elements caused by the temperature rise.
The present invention is based on the practical circuit working principle of the isolated power supply to overcome the shortcomings of the prior art heat dissipation control circuit, and proposes that the working element in the isolated power supply, such as an inductor or a resistor element, can be utilized to directly respond to the electrical state change (such as voltage, current …, etc.) during the practical operation, so as to detect the temperature to be raised in advance, and immediately directly operate the heat dissipation fan 1 to rotate or perform the heat dissipation treatment in advance for controlling the rotating speed, thereby eliminating the shortcomings of noise and power loss caused by the prior art control circuit 10 and the heat dissipation time delay caused by the prior art control circuit 10.
It should be noted that the primary side of the transformer 102 is shown on the same side as the primary winding W1 of the transformer 102, and the circuits on the primary side of the transformer 102 are electrically connected to the reference potential REF; the secondary side of the transformer 102 is on the same side as the winding W2 on the secondary side of the transformer 102, and the circuits on the secondary side of the transformer 102 are commonly connected to the ground potential GND; the feedback signal transmission circuit 107 is coupled between the primary side and the secondary side.
Fig. 4 shows a second embodiment according to the invention. Referring to fig. 4, a schematic diagram of an isolated power supply 100 according to an embodiment of the invention is shown. The isolated power supply 100 includes an AC rectifying and filtering unit 101, a transformer 102, a primary switch 103, a primary driving circuit 104, a secondary control circuit 105, a feedback signal transmission circuit 107, a current sensing circuit 108, an output sampling circuit 109, a temperature sensing device 110, an input signal transmission circuit 111, and a secondary rectifying and filtering unit 112. In the present embodiment, the isolated power supply 100 further includes a temperature sensing device 110, and the cooling fan 1 can be operated according to a temperature sensing signal Stm generated by the temperature sensing device 110, in addition to being operated/not operated according to the cooling control signal Shd, or/and controlling the rotation speed thereof during operation, wherein the temperature sensing device 110 generates the temperature sensing signal Stm according to the ambient temperature. The temperature sensing device 110 includes, for example and without limitation, a thermistor as shown in fig. 4.
The present embodiment is different from the first embodiment in that a more specific embodiment of the AC rectifying and filtering unit 101 is shown in the present embodiment. The AC rectifying and filtering unit 101 is, for example, but not limited to, a bridge type AC rectifying and filtering circuit as shown in fig. 4.
The primary side driving circuit 104 is disposed on the primary side of the transformer 102, and is configured to generate a switching signal GATE to operate the primary side switch 103 according to a coupling feedback signal Vfb generated by the feedback signal Sfb, so as to convert the input voltage Vin into the output voltage Vout. The primary-side switch 103 is, for example, but not limited to, a power switch having a single MOS device as shown in fig. 4.
The secondary control circuit 105 is located on the secondary side of the transformer 102, and includes a feedback signal processing unit 1051 and a heat dissipation control circuit 1052. The feedback signal processing unit 1051 receives the output voltage Vout to generate a feedback signal Sfb. In this embodiment, the feedback signal processing unit 1051 is, for example, a node coupled to the output voltage Vout, and can directly provide the output voltage Vout to the feedback signal processing unit 1051.
In the present embodiment, the heat dissipation control circuit 1052, for example, feeds back the tap voltage Vs of the secondary winding W3 in the feedback signal transmission circuit 107 to generate the heat dissipation control signal Shd. The feedback secondary side winding W3 receives a feedback signal Sfb related to the output voltage Vout; therefore, the tap voltage Vs obtained from the feedback secondary winding W3 is also related to the output voltage Vout to the output power supply.
The feedback signal transmitting circuit 107 is coupled between the primary side driving circuit 104 and the secondary side control circuit 105, and converts the feedback signal Sfb into the coupling feedback signal Vfb in a non-contact induction manner, such as but not limited to an electromagnetic induction manner of a transformer as shown in fig. 4, for inputting to the primary side driving circuit 104. In the present embodiment, the feedback signal transmission circuit 107 is, for example, but not limited to, a transformer as shown in fig. 4. The heat dissipation control circuit 1052 is used for generating a heat dissipation control signal Shd according to the output power and the output power to control the heat dissipation fan 1.
In a preferred embodiment, when the tap voltage Vs of the feedback secondary winding W3 exceeds a predetermined threshold, it indicates that the output voltage Vout is relatively high, which usually indicates that the output power is increased, and the temperature will rise as well, so that there is a heat dissipation requirement, therefore, the heat dissipation control signal Shd can be generated by the tap voltage Vs, and when the output voltage Vout is relatively high, the heat dissipation function is enabled, so as to operate the heat dissipation fan 1.
Fig. 5 shows a third embodiment according to the invention. Referring to fig. 5, a schematic diagram of an isolated power supply 100 according to an embodiment of the invention is shown. The present embodiment is different from the second embodiment in that the output sampling circuit 109 of the present embodiment is coupled to the secondary winding W2 for generating an output sampling signal Sop related to the output power source, i.e. the output voltage Vout is multiplied by the output current Iout, according to the output current Iout flowing through the secondary winding, and the heat dissipation control circuit 1052 generates the heat dissipation control signal Shd according to the output sampling signal Sop. As shown in fig. 5, the output sampling circuit 109 includes, for example but not limited to, an output sampling resistor Ro connected in series with the secondary winding W2, and the output sampling resistor Ro generates the heat dissipation control signal Sop according to the output current Iout or the output sampling voltage difference Vro across the output sampling resistor Ro.
Fig. 6 shows a fourth embodiment according to the invention. FIG. 6 shows a schematic diagram of a more specific embodiment of the thermal dissipation control circuit 1052 according to the present invention. As shown in fig. 6, the heat dissipation control circuit 1052 includes, for example, a feedback tap amplifying circuit AM1, coupled to the feedback secondary winding W3 in the second embodiment, for comparing the tap voltage Vs with the reference voltage Vref to generate the heat dissipation control signal Shd.
Fig. 7 shows a fifth embodiment according to the invention. Fig. 7 shows a schematic diagram of another more specific embodiment of the heat dissipation control circuit 1052 according to the present invention. As shown in fig. 7, the heat dissipation control circuit 1052, for example, includes an output sampling amplifying circuit AM2, which is coupled to the output sampling circuit 109 in the third embodiment, for generating the heat dissipation control signal Shd according to the sampling signal Sop. As shown in fig. 7, the output sampling amplifying circuit AM2, for example, receives the output sampling voltage difference Vr and generates the heat dissipation control signal Shd.
Fig. 8 shows a sixth embodiment according to the invention. Referring to fig. 8, a schematic diagram of an isolated power supply 200 according to an embodiment of the invention is shown. The isolated power supply 200 includes an AC rectifying and filtering unit 201, a transformer 202, a primary switch 203, a primary driving circuit 204, a secondary control circuit 205, a feedback signal transmission circuit 207, a current sensing circuit 208, an output sampling circuit 209, a temperature sensing device 210, an input signal transmission circuit 211, and a secondary rectifying and filtering unit 212.
The AC voltage Vac is rectified by the AC rectifying/smoothing unit 201 to generate an input voltage Vin. The AC rectifying and filtering unit 201 is, for example, but not limited to, a bridge type AC rectifying and filtering unit. In the isolated power supply 200, the transformer 202 includes a primary winding W1 and a secondary winding W2 coupled to each other by electromagnetic induction (electromagnetic induction). The primary winding W1 is coupled to receive an input power having an input voltage Vin.
The primary switch 203 is coupled to the primary winding W1 for switching the primary winding W1 to control the on-time of the primary winding W1, so as to generate an output power with an output voltage Vout at the secondary winding W2 by electromagnetic induction, and provide a load current IDL to the load circuit 206 coupled to the output voltage Vout. In the present embodiment, the primary-side switch 203 includes, for example but not limited to, an upper-bridge switch UG and a lower-bridge switch LG, and the upper-bridge switch UGATE and the lower-bridge switch LGATE receive the switching signal GATE and the lower-bridge switching signal LGATE respectively to switch the primary-side winding W1, wherein the upper-bridge switch UG and the lower-bridge switch LG are not turned on simultaneously.
The primary-side driving circuit 204 is located at the primary side of the transformer 202, and is configured to generate a switching signal GATE according to a coupling feedback signal Vfb generated by the feedback signal Sfb to operate the primary-side switch 203, so as to convert the input voltage Vin into the output voltage Vout.
The secondary side rectifying and filtering unit 212 receives the signal generated by the secondary side winding W2, generates an output signal after rectifying and filtering, and outputs the output signal to the input/output sampling circuit 109 through the filter capacitor C as shown in fig. 8, thereby generating the output voltage Vout and the load current IDL flowing through the load circuit 106.
The secondary control circuit 205 is located on the secondary side of the transformer 202, and includes a feedback signal processing unit 2051, a heat dissipation control circuit 2052, an output signal processing unit 2053, an input signal processing unit 2054, and an alarm processing unit 2055. The feedback signal processing unit 2051 receives an output sampling signal related to the output power to generate a feedback signal Sfb. In the present embodiment, for example, the output voltage Vout is used as an output sampling signal related to the output power source. In this embodiment, the feedback signal processing unit 2051 may further generate an output power related signal Vs2 according to the output voltage Vout, so as to be input to the heat dissipation control circuit 2052 to generate the heat dissipation control signal Shd.
The heat dissipation control circuit 2052 is configured to generate a heat dissipation control signal Shd according to the input power and the output power to control the heat dissipation fan 1. In the present embodiment, the heat dissipation control circuit 2052 generates the heat dissipation control signal Shd according to, for example, the output sampling signal Sop of the output power related signal, the coupling input signal Vrs2 of the input power related signal, and the temperature sensing signal Stm related to the ambient operating environment temperature, so as to adjust the rotation speed of the heat dissipation fan 1.
The output signal processing unit 2053 is coupled to the output sampling circuit 209, and is configured to receive the output sampling signal Sop generated by the output sampling circuit 209 and related to the output power to generate an output power related signal Vrl2, which is input to the heat dissipation control circuit 2052 to generate a heat dissipation control signal Shd.
The input signal processing unit 2054 is coupled to the input signal transmitting circuit 211, and is configured to receive a coupling input signal Vrs2 related to an input power generated by the input signal transmitting circuit 211, so as to generate an input power related signal Vrs3, which is input to the heat dissipation control circuit 2052, so as to generate a heat dissipation control signal Shd.
The alarm processing unit 2055 is coupled to the feedback signal processing unit 2051 and the heat dissipation control circuit 2052, respectively, and is configured to generate an input power alarm signal, an output power alarm signal, and a temperature alarm signal according to the input power, the output power, and the heat dissipation control signal Shd. The alarm processing unit 2055 also generates an under-voltage alarm signal or an over-voltage alarm signal according to whether the output voltage Vout is higher than the upper limit of the output voltage or lower than the lower limit of the output voltage.
In detail, the alarm processing unit 2055 may provide a warning display, such as but not limited to an LED light signal display, and may immediately display the abnormal heat dissipation temperature or output voltage, so as to quickly and correctly perform the necessary safety processing measures of the corresponding circuit or device, and quickly recover the normal operation of the power supply.
When one or more of the 3 input parameters exceed the power supply operation safety specification, the warning processing unit 2055 outputs one or more warning display signals ERRRS, ERRRL and ERRTEMP, respectively.
If the output voltage Vout representing the output power generated by the load circuit 206 is lower than the lower limit of the output voltage or higher than the upper limit of the output voltage, the output feedback processing unit 2051 outputs a corresponding low voltage warning signal UVP or OVP. When one or two of the 2 input parameters exceed the power supply operation safety specification, the warning display processing unit 2055 correspondingly outputs one or two warning display signals ERRUVP or ERROVP, respectively.
The feedback signal transmission circuit 207 is coupled between the primary-side driving circuit 204 and the secondary-side control circuit 205, and converts the feedback signal Sfb into a coupling feedback signal Vfb in a non-contact sensing manner for inputting to the primary-side driving circuit 204.
The current sensing circuit 208 is disposed on the primary side of the transformer 202 and connected in series with the primary-side switch 203 for generating an input power-related signal Vrs1 according to a switching current flowing through the primary-side switch 203. In the present embodiment, the current sensing circuit 208 includes, for example, a resistor RS1 connected in series with the primary-side switch 203, and a voltage drop generated by a resistor RS1 as the input power related signal Vrs1 is generated by a switching current flowing through the primary-side switch 203 and also flowing through a resistor RS 1.
The output sampling circuit 209 is coupled to the secondary winding W2 for generating an output sampling signal Sop related to the output power according to the output current flowing through the secondary winding W2, and the heat dissipation control circuit 2052 generates the heat dissipation control signal Shd according to the output sampling signal Sop.
The input signal transmitting circuit 211 is coupled between the primary switch 203 and the secondary control circuit 205, and configured to convert an input power related signal Vrs1 related to a switching current into a coupled input signal Vrs2 by a non-contact sensing method according to the switching current flowing through the primary switch 203, and transmit the coupled input signal Vrs2 to the secondary control circuit 205, so that the heat dissipation control circuit 2052 generates a heat dissipation control signal Shd according to the input power related signal Vrs 1.
Fig. 9 shows a seventh embodiment according to the invention. Referring to fig. 9, a schematic diagram of an isolated power supply 200 according to an embodiment of the invention is shown. The difference between this embodiment and the sixth embodiment is that in this embodiment, the input signal transmitting circuit 211 includes, for example, a transformer, and converts an input power-related signal Vrs1 related to a switching current into a coupled input signal Vrs2 in an electromagnetic induction manner; instead of as shown in fig. 8, the input signal transfer circuit 211 includes an optocoupler to convert the input power-related signal Vrs1 with respect to the switching current into a coupled input signal Vrs2 in a photo-inductive manner.
The present invention has been described with respect to the preferred embodiments, but the above description is only for the purpose of making the content of the present invention easy to understand for those skilled in the art, and is not intended to limit the scope of the present invention. The embodiments described are not limited to separate applications, but may be applied in combination. In addition, the term "processing or calculating or generating an output result according to a signal" in the present invention is not limited to the signal itself, and includes performing voltage-current conversion, current-voltage conversion, and/or ratio conversion on the signal, if necessary, and then performing processing or calculation according to the converted signal to generate an output result. It is understood that those skilled in the art can devise various equivalent variations and combinations, which are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Accordingly, the scope of the present invention should be determined to encompass all such equivalent variations as described above.
Claims (17)
1. An isolated power supply, comprising:
a transformer including a primary winding and a secondary winding coupled to each other by electromagnetic induction, wherein the primary winding is electrically coupled to an input power source;
a primary side switch coupled to the primary side winding for switching the primary side winding to convert the input power into an output power from the secondary side winding;
a primary side driving circuit coupled to the primary side switch for generating a switching signal according to a feedback signal to operate the primary side switch;
a secondary side control circuit for generating the feedback signal according to the output power;
a feedback signal transmission circuit coupled between the primary side drive circuit and the secondary side control circuit for transferring the feedback signal to the primary side drive circuit in a non-contact induction mode; and
an output sampling circuit coupled to the secondary side winding for generating an output sampling signal related to the output power according to an output current flowing through the secondary side winding;
the secondary side control circuit comprises a heat dissipation control circuit used for generating a heat dissipation control signal according to the output power supply and the input power supply so as to control a heat dissipation fan;
the heat dissipation control circuit generates the heat dissipation control signal according to the output sampling signal;
the secondary side control circuit also comprises an output signal processing unit which is used for generating an output power supply related signal according to the output sampling signal so as to input the output power supply related signal into the heat dissipation control circuit.
2. The isolated power supply of claim 1, further comprising an input signal transmission circuit coupled between the primary-side switch and the secondary-side control circuit for transmitting an input power related signal related to the switching current to the secondary-side control circuit in a non-contact sensing manner according to a switching current flowing through the primary-side switch, such that the heat dissipation control circuit generates the heat dissipation control signal according to the input power related signal.
3. The isolated power supply according to claim 1, wherein the feedback signal transmitting circuit comprises a feedback transformer, and the heat dissipation control circuit generates the heat dissipation control signal according to a tap voltage of a feedback secondary winding of the feedback transformer.
4. The isolated power supply of claim 3, wherein the thermal dissipation control circuit comprises a feedback tap amplifier circuit coupled to the feedback secondary winding for generating the thermal dissipation control signal according to the tap voltage and a reference voltage.
5. The isolated power supply of claim 1, further comprising a temperature sensing device coupled to the heat dissipation fan for generating a temperature sensing signal according to an ambient temperature to control the heat dissipation fan.
6. The isolated power supply of claim 1, wherein the primary side switch comprises an upper bridge switch and a lower bridge switch, and the upper bridge switch and the lower bridge switch receive an upper bridge switching signal and a lower bridge switching signal of the switching signal respectively to switch the primary side winding, and the upper bridge switch and the lower bridge switch are not turned on simultaneously.
7. The isolated power supply of claim 1, wherein the secondary control circuit further comprises a feedback signal processing unit for generating the feedback signal according to the output power.
8. The isolated power supply of claim 1, wherein the secondary control circuit further comprises an alarm processing unit for generating an input power alarm signal, an output power alarm signal, and a temperature alarm signal according to the input power, the output power, and the heat dissipation control signal.
9. The isolated power supply of claim 8, wherein the alarm processing unit further generates an under-voltage alarm signal or an over-voltage alarm signal according to whether an output voltage is higher than an upper output voltage limit or lower than a lower output voltage limit.
10. A secondary side control circuit for use in an isolated power supply, the secondary side control circuit comprising:
a feedback signal processing unit for generating a feedback signal according to an output power;
a heat dissipation control circuit for generating a heat dissipation control signal according to the output power supply and an input power supply to control a heat dissipation fan; and
an output signal processing unit for generating an output power supply related signal according to an output sampling signal to input the heat dissipation control circuit;
the feedback signal is transferred to the primary side drive circuit in a non-contact induction mode through a feedback signal transmission circuit coupled between a primary side drive circuit and the secondary side control circuit;
the primary side driving circuit generates a switching signal according to the feedback signal to operate a primary side switch;
the primary side switch is used for switching a primary side winding of a transformer according to the switching signal so as to convert the input power supply into the output power supply through the transformer by electromagnetic induction;
the secondary side winding is coupled with an output sampling circuit, the output sampling circuit is used for generating the output sampling signal related to the output power supply according to an output current flowing through the secondary side winding, and the heat dissipation control circuit generates the heat dissipation control signal according to the output sampling signal.
11. The secondary-side control circuit of claim 10, wherein the isolated power supply further comprises an input signal transmission circuit coupled between the primary-side switch and the secondary-side control circuit for transmitting an input power related signal related to the switching current to the secondary-side control circuit in a non-contact sensing manner according to a switching current flowing through the primary-side switch, so that the heat dissipation control circuit generates the heat dissipation control signal according to the input power related signal.
12. The secondary-side control circuit of claim 10 wherein the feedback signal transmission circuit comprises a feedback transformer, and the heat dissipation control circuit generates the heat dissipation control signal based on a tap voltage of a feedback secondary-side winding in the feedback transformer.
13. The secondary-side control circuit of claim 12 wherein the heat dissipation control circuit comprises a feedback tap amplifier circuit coupled to the feedback secondary-side winding for generating the heat dissipation control signal based on the tap voltage and a reference voltage.
14. The secondary-side control circuit of claim 10 wherein the heat dissipation fan further operates in response to a temperature sensing signal generated by a temperature sensing device, wherein the temperature sensing device generates the temperature sensing signal in response to an ambient temperature.
15. The secondary-side control circuit of claim 10 wherein the primary-side switch comprises an upper-bridge switch and a lower-bridge switch for receiving an upper-bridge switching signal and a lower-bridge switching signal of the switching signal respectively to switch the primary-side winding, wherein the upper-bridge switch and the lower-bridge switch are not turned on simultaneously.
16. The secondary-side control circuit of claim 10 further comprising an alarm processing unit for generating an input power alarm signal, an output power alarm signal, and a temperature alarm signal according to the input power, the output power, and the heat dissipation control signal.
17. The secondary-side control circuit of claim 16 wherein the alarm processing unit further generates an under-voltage alarm signal or an over-voltage alarm signal according to whether an output voltage is higher than an upper output voltage limit or lower than a lower output voltage limit.
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| CN201911413855.6A CN113131743B (en) | 2019-12-31 | 2019-12-31 | Isolated power supply and secondary side control circuit thereof |
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| CN201911413855.6A CN113131743B (en) | 2019-12-31 | 2019-12-31 | Isolated power supply and secondary side control circuit thereof |
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| TWI817586B (en) * | 2022-06-29 | 2023-10-01 | 宏碁股份有限公司 | Power supply device with tunable heat dissipation function |
| CN115407857B (en) * | 2022-10-20 | 2023-04-07 | 中电长城圣非凡信息系统有限公司 | Ruggedized computer fan control system based on double-spectrum image |
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| TWM470448U (en) * | 2013-07-29 | 2014-01-11 | Etasis Electronics Corp | Temperature sensing cooling device and power supply system thereof |
| CN208112515U (en) * | 2018-04-26 | 2018-11-16 | 保锐科技股份有限公司 | Power supply device with fan full-speed operation switching switch |
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