CN109802363B - Synchronous rectification circuit, synchronous rectification protection method, synchronous rectification protection device and charger - Google Patents
Synchronous rectification circuit, synchronous rectification protection method, synchronous rectification protection device and charger Download PDFInfo
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Abstract
The embodiment of the invention relates to a synchronous rectification circuit and a protection method, a synchronous rectification protection device and a charger, wherein the synchronous rectification circuit comprises a transformer, a first power tube, a synchronous rectification protection device and a primary side controller, and the synchronous rectification protection device comprises a temperature detection unit; the transformer comprises a primary winding, a secondary winding and an auxiliary winding; one end of the primary winding is connected with a power supply, and the other end of the primary winding is connected with the drain electrode of the first power tube; the secondary winding is connected with the synchronous rectification protection device; the auxiliary winding is connected with the primary side controller; when the temperature detection unit detects that the temperature of the synchronous rectification circuit exceeds a preset first temperature threshold value, the secondary winding sends a thermal protection starting pulse signal, the starting pulse signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller decodes the starting pulse signal and sends a closing signal to the first power tube.
Description
Technical Field
The invention belongs to the field of switching power supplies, and particularly relates to a synchronous rectification circuit, a synchronous rectification protection method, a synchronous rectification protection device and a charger.
Background
With the rapid development of large-screen smart phones, the battery capacity of the mobile phone is larger and larger, and accordingly, the requirement on the charging speed of the battery is higher and higher.
Some super fast charging and flash charging in the prior art have a charging current of up to 5A, and if the secondary freewheeling diode adopts a general schottky, 2w of power consumption will be generated, and these power consumption will be wasted on the freewheeling diode. In order to solve the loss of the freewheel diode, most quick charging chargers mostly adopt synchronous rectification circuits to replace freewheel diodes, so that the freewheel diodes are replaced by internal synchronous rectification mos tubes, and only 0.2W of energy consumption is needed, so that the charging efficiency is greatly improved.
However, in the practical application process, if the output part is short-circuited or other abnormal conditions occur, the synchronous rectification circuit is continuously heated, and the primary side control chip and the power tube are in the normal temperature range, so that the primary side control thermal protection cannot be started, and the whole system still works according to the existing power, so that the temperature of the synchronous rectification circuit is higher and higher, and even the chip is burnt.
Therefore, for the above-mentioned situation, that is, if the output portion is shorted or other abnormal conditions occur, the synchronous rectification circuit continuously generates heat, and the synchronous rectification control chip generally has the following two response modes when the temperature exceeds a certain temperature (for example, 130 degrees to 150 degrees):
firstly, the synchronous rectification circuit continuously generates heat because of no thermal protection unit;
Secondly, although the thermal protection unit is arranged in the prior art for turning off the power tube built-in by synchronous rectification, at the moment, the parasitic body diode of the power tube is conducted, and the voltage drop of the diode is 0.7V, so that the conducted heating value is higher, namely the synchronous rectification circuit has no thermal protection function in practice, and once the synchronous rectification circuit enters a thermal protection stage, the power tube is likely to be damaged, and the use of the whole charger is further influenced.
Disclosure of Invention
In view of the above, the present invention provides a synchronous rectification circuit and protection method, a synchronous rectification protection device and a charger, wherein a temperature detection unit is arranged in the synchronous rectification protection device, when the temperature detection unit detects that the temperature of the synchronous rectification circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device sends a thermal protection starting signal to a secondary winding, the thermal protection starting signal is transmitted to a primary side controller through an auxiliary winding, and the primary side controller turns off a first power tube after receiving the thermal protection starting signal; when the temperature detection unit detects that the temperature of the synchronous rectification circuit is lower than a preset second temperature threshold value, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding, the thermal protection closing signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller starts the first power tube after receiving the thermal protection closing signal.
The technical scheme of the invention is as follows:
In a first aspect, an embodiment of the present invention provides a synchronous rectification circuit, including a transformer, a first power tube, a synchronous rectification protection device, and a primary side controller, where the synchronous rectification protection device includes a temperature detection unit;
The transformer comprises a primary winding, a secondary winding and an auxiliary winding; one end of the primary winding is connected with a power supply, and the other end of the primary winding is connected with the drain electrode of the first power tube; the secondary winding is connected with the synchronous rectification protection device; the auxiliary winding is connected with the primary side controller;
When the temperature detection unit detects that the temperature of the synchronous rectification circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device sends a thermal protection starting signal to the secondary winding, the thermal protection starting signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller turns off the first power tube after receiving the thermal protection starting signal;
when the temperature detection unit detects that the temperature of the synchronous rectification circuit is lower than a preset second temperature threshold value, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding, the thermal protection closing signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller starts the first power tube after receiving the thermal protection closing signal.
In a second aspect, an embodiment of the present invention provides a protection method for a synchronous rectification circuit, where the synchronous rectification circuit includes a transformer, a first power tube, a synchronous rectification protection device, and a primary side controller, and the synchronous rectification protection device includes a temperature detection unit; the transformer comprises a primary winding, a secondary winding and an auxiliary winding; the protection method comprises the following steps:
When the temperature detection unit detects that the temperature of the synchronous rectification circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device sends a thermal protection starting signal to the secondary winding, the thermal protection starting signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller turns off the first power tube after receiving the thermal protection starting signal;
when the temperature detection unit detects that the temperature of the synchronous rectification circuit is lower than a preset second temperature threshold value, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding, the thermal protection closing signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller starts the first power tube after receiving the thermal protection closing signal.
In a third aspect, an embodiment of the present invention provides a synchronous rectification protection device for a transformer circuit, where the transformer circuit includes a primary winding, a secondary winding, an auxiliary winding, a first power tube and a primary side controller, the synchronous rectification protection device includes a temperature detection unit, a second power tube and a switch controller, an output end of the temperature detection unit is connected with one end of the switch controller, and another end of the switch controller is connected with the second power tube;
When the temperature detection unit detects that the temperature of the transformer circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device sends a thermal protection starting signal to the secondary winding, the thermal protection starting signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller turns off the first power tube after receiving the thermal protection starting signal;
When the temperature detection unit detects that the temperature of the transformer circuit is lower than a preset second temperature threshold value, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding, the thermal protection closing signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller starts the first power tube after receiving the thermal protection closing signal.
In a fourth aspect, an embodiment of the present invention provides a charger, where the charger includes the synchronous rectification circuit described above.
In a fifth aspect, an embodiment of the present invention provides a charger, where the charger includes the synchronous rectification protection device described above.
According to the embodiment of the invention, the temperature detection unit is arranged in the synchronous rectification protection device, when the temperature detection unit detects that the temperature of the synchronous rectification circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device sends a thermal protection starting signal to the secondary winding, the thermal protection starting signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller turns off the first power tube after receiving the thermal protection starting signal; when the temperature detection unit detects that the temperature of the synchronous rectification circuit is lower than a preset second temperature threshold value, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding, the thermal protection closing signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller starts the first power tube after receiving the thermal protection closing signal; therefore, the heat protection of the synchronous rectification circuit in the embodiment of the invention is realized, and the damage of the first power tube is reduced.
Drawings
Fig. 1 is a schematic diagram of a synchronous rectification circuit according to an embodiment of the present invention;
Fig. 2 is an external application schematic diagram of a synchronous rectification circuit according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a synchronous rectification protection device according to an embodiment of the present invention.
Wherein 10 is a first power tube; 20 is a synchronous rectification protection device; 30 is a primary side controller; l 0 is a primary winding, L 1 is a secondary winding, and L 2 is an auxiliary winding; r 1 is a first resistor and R 2 is a second resistor; c is a capacitor.
Detailed Description
The present invention will be described in detail below with reference to the embodiments shown in the drawings, but it should be understood that the embodiments are not limited to the present invention, and functional, method, or structural equivalents and alternatives according to the embodiments are within the scope of protection of the present invention by those skilled in the art.
Example 1
1. Structure of synchronous rectifying circuit
Fig. 1 is a schematic structural diagram of a synchronous rectification circuit according to an embodiment of the present invention, and fig. 3 is a schematic structural diagram of a synchronous rectification protection device according to an embodiment of the present invention; referring to fig. 1 and 3, a synchronous rectification circuit includes a transformer, a first power tube 10, a synchronous rectification protection device 20, and a primary side controller 30, wherein the synchronous rectification protection device 20 includes a temperature detection unit; in this embodiment, the base emitter junction of the diode or triode, i.e. the PN junction, may be used as a thermosensitive element for detecting the temperature of the synchronous rectification circuit;
The transformer comprises a primary winding L 0, a secondary winding L 1 and an auxiliary winding L 2; one end of the primary winding L 0 is connected with a power supply, and the other end of the primary winding L 0 is connected with the drain electrode of the first power tube 10; the secondary winding L 1 is connected with the synchronous rectification protection device 20; the auxiliary winding L 2 is connected with the primary side controller 30;
When the temperature detection unit detects that the temperature of the synchronous rectification circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device 20 sends a thermal protection starting signal to the secondary winding L 1, the thermal protection starting signal is transmitted to the primary side controller 30 through the auxiliary winding L 2, and the primary side controller 30 closes the first power tube 10 after receiving the thermal protection starting signal;
when the temperature detecting unit detects that the temperature of the synchronous rectification circuit is lower than a preset second temperature threshold, the synchronous rectification protection device 20 sends a thermal protection closing signal to the secondary winding L 1, the thermal protection closing signal is transmitted to the primary side controller 30 through the auxiliary winding L 2, and the primary side controller 30 starts the first power tube 10 after receiving the thermal protection closing signal.
The synchronous rectification protection device 20 in this embodiment further includes a second power tube and a switch controller, where an output end of the temperature detection unit is connected to one end of the switch controller, and the other end of the switch controller is connected to the second power tube; the temperature detection unit may use a PN junction of a diode or a triode as a thermosensitive element. The forward voltage of the PN junction depends on the band gap of silicon, and the temperature coefficient is independent of the process and is approximately-2 mV/DEG C. By comparing the output of the thermosensitive element with a reference voltage having no temperature coefficient, it is possible to detect whether the thermosensitive element exceeds a certain temperature. The reference voltage is set to be equal to the output voltage of the thermosensitive element at the overheat temperature. And the output voltage of the thermosensitive element and the reference voltage are used as positive and negative inputs of a comparator, when the temperature reaches the thermal shutdown temperature, the two voltages are equal, the output of the comparator is turned over, and the switch controller controls the second power tube to send a thermal protection enabling signal.
Specifically, the first end of the synchronous rectification protection device 20 is also connected with one end of the capacitor C, and the second end of the synchronous rectification protection device 20 is grounded; the source electrode of the first power tube 10 is grounded;
One end of the secondary winding L 1 is connected with a capacitor C, and the other end of the capacitor C is grounded;
The other end of the first resistor R 1 is connected with one end of the second resistor R 2;
One end of the primary side controller 30 is connected with the grid electrode of the first power tube 10, the other end of the primary side controller 30 is respectively connected with the other end of the first resistor R 1 and one end of the second resistor R 2, and the other end of the second resistor R 2 is grounded; preferably, the first resistor R 1 is a sampling resistor.
Preferably, the primary side controller 30 may be a primary side controller of the model csc 7158.
Fig. 2 is an external application schematic diagram of a synchronous rectification circuit according to an embodiment of the present invention; referring to fig. 2, in this embodiment, the first power tube 10 may be packaged in the primary side controller 30, wherein a first end of the primary winding L 0 is connected to a power load, and the other end of the primary winding L 0 is connected to pins 5 and 6 (i.e., drains) of the primary side controller 30. The pin 1-VDD end of the primary side controller 30 is connected with one end of an external load R 4, the pin 3-feedback FB end is connected with the voltage division points of R 1 and R 2, the pin 4-enabling pin CS is connected with one end of a collector load resistor R CS, and the other end of R CS is grounded;
One end of the secondary winding L 1 is connected to the SW end (i.e., the third end) of the synchronous rectification protection device 20; the other end of the secondary winding L 1 is connected with the voltage VCC (i.e. first end) end of the synchronous rectification protection device 20; the capacitor C is connected to the ground (i.e., the second end) of the synchronous rectification protection device 20;
One end of the auxiliary winding L 2 is connected in series with a first resistor R 1 and is connected with the primary side controller 30, and the other end of the auxiliary winding L 2 is grounded.
2. Working process of synchronous rectification circuit
A temperature detection unit is arranged in the synchronous rectification protection device 20, when the temperature detection unit detects that the temperature of the synchronous rectification circuit exceeds or is equal to a preset first temperature threshold value, the synchronous rectification protection device sends a thermal protection starting pulse signal to a secondary winding L 1, the thermal protection starting pulse signal conducts a second power tube in the synchronous rectification protection device 20, the second power tube transmits the thermal protection starting pulse signal to a secondary winding L 1 after being conducted, the secondary winding L 1 is also conducted immediately, the secondary winding L 1 transmits the thermal protection starting pulse signal to a primary side controller 30 through an auxiliary winding L 2, and the primary side controller 30 decodes the thermal protection starting pulse signal and sends a closing signal to the first power tube 10;
When the temperature detection unit detects that the temperature of the synchronous rectification circuit is lower than a preset second temperature threshold value, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding L 1, the thermal protection closing signal is transmitted to the primary side controller 30 through the auxiliary winding L 2, and the primary side controller 30 starts the first power tube 10 after receiving the thermal protection closing signal so as to realize the thermal protection of the synchronous rectification circuit of the embodiment.
Specifically, the synchronous rectification circuit according to one embodiment of the present invention operates as follows:
First, the primary side controller 30 sends an on signal to the first power tube 10, the first power tube 10 is turned on, and since the drain electrode of the first power tube 10 is connected with the other end of the primary winding L 0, energy is stored in the primary winding L 0, when the current of the primary winding L 0 reaches a preset current threshold, the first power tube 10 is turned off, and the process of energy storage of the primary winding L 0 by the first power tube 10 is ended.
Preferably, the preset current threshold value is automatically adjusted according to the output load, for example, 3A-5A; it will be appreciated that the preset current threshold may be other values, and is not limited to the current range shown in this embodiment.
Then, the transformer starts to discharge through the secondary winding L 1, the secondary winding L 1 charges the capacitor C through the synchronous rectification protection device 20, and the charged capacitor C is used for supplying power to an output load (such as a charger, an adapter and the like);
During the on period of the primary side controller 30, the heat of the synchronous rectification circuit is in an accumulation stage, if the synchronous rectification circuit is short-circuited or otherwise abnormal, the current of the temperature detection unit is rapidly increased, so that the temperature of the whole synchronous rectification circuit is increased, and when the temperature of the synchronous rectification circuit exceeds or equals to a preset temperature threshold value, the thermal protection of the synchronous rectification circuit is started.
Preferably, the preset temperature threshold may be 130 ° to 150 °, and it is understood that in other embodiments, the preset temperature threshold may also be a temperature value in other ranges, which is not limited herein.
Specifically, the thermal protection initiation may include the steps of:
firstly, when the temperature of the synchronous rectification circuit exceeds or equals to a preset temperature threshold, the synchronous rectification protection device 20 sends a thermal protection start pulse signal to the secondary winding L 1 in the time when the secondary winding L 1 is demagnetized, and the thermal protection start pulse signal is transmitted to the primary side controller 30 through the auxiliary winding L 2, the first resistor R 1 and the second resistor R 2; the secondary side degaussing mainly refers to a process that the secondary winding L 1 is in a discharging process, and the secondary inductance current is linearly reduced from the maximum value;
then, the primary side controller 30 decodes the thermal protection start pulse signal to obtain secondary side thermal protection data;
Then, the primary side controller 30 sends a shutdown signal to the first power tube 10, and the first power tube 10 is turned off, so that the primary winding L 0 of the transformer cannot store energy, that is, no current is transmitted to the primary side controller 30 through the secondary winding L 1, and the temperature of the primary side controller 30 is reduced.
When the temperature detection unit detects that the temperature of the synchronous rectification circuit is lower than a preset second temperature threshold value, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding L 1, the thermal protection closing signal is transmitted to the primary side controller 30 through the auxiliary winding L 2, and the primary side controller 30 starts the first power tube 10 after receiving the thermal protection closing signal so as to realize the thermal protection of the synchronous rectification circuit of the embodiment.
The synchronous rectification circuit in this embodiment may be applied to a flyback switching power supply, in order to improve the efficiency of the synchronous rectification circuit, the secondary winding L 1 may use synchronous rectification, once the abnormal heating condition exists in synchronous rectification, when the whole synchronous rectification circuit heats more than or equal to 130 ° to 150 °, because the maximum output power of the synchronous rectification circuit is controlled by the primary side controller 30, the synchronous rectification protection device 20 of the secondary winding L 1 is only used to detect the temperature of the synchronous rectification protection device 20, and cannot close the switching state of the synchronous rectification circuit, so that the synchronous rectification circuit needs to be transmitted to the primary side controller 30 through a transformer, and after the primary side controller 30 receives a thermal protection signal, the first power tube 10 is turned off; preferably, in this embodiment, the thermal protection function of the integral synchronous rectification circuit may be implemented by a hiccup restart mode, so as to restart the synchronous rectification circuit.
Example two
The embodiment provides a protection method of a synchronous rectification circuit; the synchronous rectification circuit comprises a transformer, a first power tube, a synchronous rectification protection device and a primary side controller, wherein the synchronous rectification protection device comprises a temperature detection unit; the transformer comprises a primary winding, a secondary winding and an auxiliary winding; the protection method comprises the following steps:
When the temperature detection unit detects that the temperature of the synchronous rectification circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device 20 sends a thermal protection starting signal to the secondary winding L 1, the thermal protection starting signal is transmitted to the primary side controller 30 through the auxiliary winding L 2, and the primary side controller 30 closes the first power tube 10 after receiving the thermal protection starting signal;
when the temperature detecting unit detects that the temperature of the synchronous rectification circuit is lower than a preset second temperature threshold, the synchronous rectification protection device 20 sends a thermal protection closing signal to the secondary winding L 1, the thermal protection closing signal is transmitted to the primary side controller 30 through the auxiliary winding L 2, and the primary side controller 30 starts the first power tube 10 after receiving the thermal protection closing signal.
Example III
The present embodiment provides a synchronous rectification protection device for a transformer circuit including a primary winding L 0, a secondary winding L 1, an auxiliary winding L 2, a first power tube 10 and a primary side controller 30,
The synchronous rectification protection device comprises a temperature detection unit, a second power tube and a switch controller, wherein the output end of the temperature detection unit is connected with one end of the switch controller, and the other end of the switch controller is connected with the second power tube;
when the temperature detection unit detects that the temperature of the transformer circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device sends a thermal protection starting signal to the secondary winding L 1, the thermal protection starting signal is transmitted to the primary side controller 30 through the auxiliary winding L 2, and the primary side controller 30 closes the first power tube 10 after receiving the thermal protection starting signal;
When the temperature detection unit detects that the temperature of the transformer circuit is lower than a preset second temperature threshold, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding L 1, the thermal protection closing signal is transmitted to the primary side controller 30 through the auxiliary winding L 2, and the primary side controller 30 starts the first power tube 10 after receiving the thermal protection closing signal.
Preferably, the first end of the synchronous rectification protection device is also connected with one end of the capacitor C, and the second end of the synchronous rectification protection device is grounded; the source electrode of the first power tube 10 is grounded;
One end of the secondary winding L 1 is connected with a capacitor, and the other end of the capacitor C is grounded;
The other end of the first resistor R 1 is connected with one end of the second resistor R 2;
One end of the primary side controller 30 is connected with the grid electrode of the first power tube 10, the other end of the primary side controller is respectively connected with the other end of the first resistor R 1 and one end of the second resistor R 2, and the other end of the second resistor R 2 is grounded.
Preferably, the temperature detection unit is a PN junction of a diode or a triode.
The synchronous rectification protection device in this embodiment is identical to the synchronous rectification protection device 20 in the first embodiment, and will not be described herein.
Example IV
The specific external configuration of the charger in this embodiment can be applied to the prior art, and only the synchronous rectification circuit involved in this embodiment will be described.
Based on the synchronous rectification circuit, the embodiment of the present invention further provides a charger including the synchronous rectification circuit according to the first embodiment, and the specific structure of the synchronous rectification circuit is not described herein.
Example five
The specific external structure of the charger in this embodiment may also be applied to the prior art, and only the synchronous rectification protection device in this embodiment will be described.
The embodiment of the present invention further provides a synchronous rectification protection device including the third embodiment, and the specific structure of the synchronous rectification protection device is not described herein in detail.
The invention has the beneficial effects that:
According to the embodiment of the invention, the temperature detection unit is arranged in the synchronous rectification protection device, when the temperature detection unit detects that the temperature of the synchronous rectification circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device sends a thermal protection starting signal to the secondary winding, the thermal protection starting signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller turns off the first power tube after receiving the thermal protection starting signal; when the temperature detection unit detects that the temperature of the synchronous rectification circuit is lower than a preset second temperature threshold value, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding, the thermal protection closing signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller starts the first power tube after receiving the thermal protection closing signal; therefore, the heat protection of the synchronous rectification circuit in the embodiment of the invention is realized, and the damage of the first power tube is reduced.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.
Claims (7)
1. The utility model provides a synchronous rectification circuit, includes transformer, first power tube, synchronous rectification protection device and primary side controller, its characterized in that: the synchronous rectification protection device comprises a temperature detection unit; the temperature detection unit is a PN junction of a diode or a triode and is used for detecting the temperature of the synchronous rectification circuit;
The transformer comprises a primary winding, a secondary winding and an auxiliary winding; one end of the primary winding is connected with a power supply, and the other end of the primary winding is connected with the drain electrode of the first power tube; the secondary winding is connected with the synchronous rectification protection device; the auxiliary winding is connected with the primary side controller;
When the temperature detection unit detects that the temperature of the synchronous rectification circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device sends a thermal protection starting signal to the secondary winding within the time of secondary side demagnetization of the secondary winding, the thermal protection starting signal is transmitted to a primary side controller through an auxiliary winding, and after receiving the thermal protection starting signal, the primary side controller decodes the thermal protection starting pulse signal to obtain secondary side thermal protection data and closes a first power tube; the secondary side degaussing refers to a process that the secondary winding is in discharge, and secondary inductance current linearly decreases from a maximum value;
When the temperature detection unit detects that the temperature of the synchronous rectification circuit is lower than a preset second temperature threshold value, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding, the thermal protection closing signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller starts the first power tube after receiving the thermal protection closing signal; the synchronous rectification protection device further comprises a second power tube and a switch controller, wherein the output end of the temperature detection unit is connected with one end of the switch controller, and the other end of the switch controller is connected with the second power tube.
2. The synchronous rectification circuit of claim 1, wherein: the synchronous rectification protection device and the secondary winding are connected with a capacitor, and the other end of the capacitor is grounded;
the auxiliary winding is connected with the primary side controller through two voltage dividing resistors;
the primary side controller is connected with the grid electrode of the first power tube, and the first power tube is packaged in the primary side controller.
3. The synchronous rectification circuit comprises a transformer, a first power tube, a synchronous rectification protection device and a primary side controller, wherein the synchronous rectification protection device comprises a temperature detection unit, and the temperature detection unit is a PN junction of a diode or a triode and is used for detecting the temperature of the synchronous rectification circuit; the transformer comprises a primary winding, a secondary winding and an auxiliary winding; the protection method is characterized by comprising the following steps of:
When the temperature detection unit detects that the temperature of the synchronous rectification circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device sends a thermal protection starting signal to the secondary winding within the time of secondary side demagnetization of the secondary winding, the thermal protection starting signal is transmitted to a primary side controller through an auxiliary winding, the primary side controller decodes the thermal protection starting pulse signal after receiving the thermal protection starting signal to obtain secondary side thermal protection data, and a first power tube is closed; the secondary side degaussing refers to a process that the secondary winding is in discharge, and secondary inductance current linearly decreases from a maximum value;
when the temperature detection unit detects that the temperature of the synchronous rectification circuit is lower than a preset second temperature threshold value, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding, the thermal protection closing signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller starts the first power tube after receiving the thermal protection closing signal.
4. A synchronous rectification protection device for a transformer circuit, the transformer circuit comprising a primary winding, a secondary winding, an auxiliary winding, a first power tube and a primary side controller, characterized in that:
the synchronous rectification protection device comprises a temperature detection unit, a second power tube and a switch controller, wherein the output end of the temperature detection unit is connected with one end of the switch controller, and the other end of the switch controller is connected with the second power tube; the temperature detection unit is a PN junction of a diode or a triode and is used for detecting the temperature of the synchronous rectification circuit;
When the temperature detection unit detects that the temperature of the transformer circuit exceeds a preset first temperature threshold value, the synchronous rectification protection device sends a thermal protection starting signal to the secondary winding within the time of secondary side demagnetization of the secondary winding, the thermal protection starting signal is transmitted to a primary side controller through an auxiliary winding, the primary side controller decodes the thermal protection starting pulse signal after receiving the thermal protection starting signal to obtain secondary side thermal protection data, and a first power tube is closed; the secondary side degaussing refers to a process that the secondary winding is in discharge, and secondary inductance current linearly decreases from a maximum value;
When the temperature detection unit detects that the temperature of the transformer circuit is lower than a preset second temperature threshold value, the synchronous rectification protection device sends a thermal protection closing signal to the secondary winding, the thermal protection closing signal is transmitted to the primary side controller through the auxiliary winding, and the primary side controller starts the first power tube after receiving the thermal protection closing signal.
5. The synchronous rectification protection device of claim 4, wherein:
the synchronous rectification protection device and the secondary winding are connected with a capacitor, and the other end of the capacitor is grounded;
the auxiliary winding is connected with the primary side controller through two voltage dividing resistors;
the primary side controller is connected with the grid electrode of the first power tube, and the first power tube is packaged in the primary side controller.
6. A charger comprising the synchronous rectification circuit of any one of claims 1-2.
7. A charger comprising the synchronous rectification protection device of any one of claims 4-5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910018147.6A CN109802363B (en) | 2019-01-09 | 2019-01-09 | Synchronous rectification circuit, synchronous rectification protection method, synchronous rectification protection device and charger |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910018147.6A CN109802363B (en) | 2019-01-09 | 2019-01-09 | Synchronous rectification circuit, synchronous rectification protection method, synchronous rectification protection device and charger |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109802363A CN109802363A (en) | 2019-05-24 |
| CN109802363B true CN109802363B (en) | 2024-06-18 |
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| CN116667678B (en) * | 2022-11-28 | 2023-12-05 | 荣耀终端有限公司 | Power supply circuit, power supply adapter and charging system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105529800A (en) * | 2014-09-28 | 2016-04-27 | 比亚迪股份有限公司 | Charging system based on secondary control and secondary control device thereof |
| CN205490188U (en) * | 2016-01-15 | 2016-08-17 | 深圳市福瑞康电子有限公司 | Take intelligent temperature control's power adapter |
| CN209169943U (en) * | 2019-01-09 | 2019-07-26 | 无锡市晶源微电子有限公司 | Circuit of synchronous rectification, synchronous rectification protective device and charger |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100550587C (en) * | 2007-08-14 | 2009-10-14 | 伊博电源（杭州）有限公司 | The synchronous rectification of the variable turn ratio or diode rectification converter |
| CN102231605B (en) * | 2011-06-30 | 2013-12-04 | 上海新进半导体制造有限公司 | Synchronous rectification control circuit of switch power supply secondary and flyback switch power supply |
| CN105449807B (en) * | 2014-09-28 | 2018-04-20 | 比亚迪股份有限公司 | Charging system and its secondary control device based on secondary control |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105529800A (en) * | 2014-09-28 | 2016-04-27 | 比亚迪股份有限公司 | Charging system based on secondary control and secondary control device thereof |
| CN205490188U (en) * | 2016-01-15 | 2016-08-17 | 深圳市福瑞康电子有限公司 | Take intelligent temperature control's power adapter |
| CN209169943U (en) * | 2019-01-09 | 2019-07-26 | 无锡市晶源微电子有限公司 | Circuit of synchronous rectification, synchronous rectification protective device and charger |
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Address after: No. 5, Xijin Road, Xinwu District, Wuxi City, Jiangsu Province, 214028 Applicant after: Wuxi Jingyuan Microelectronics Co.,Ltd. Address before: Room 209, building a, block 106-c, national high tech Industrial Development Zone, Wuxi City, Jiangsu Province, 214028 Applicant before: Wuxi Jingyuan Microelectronics Co.,Ltd. |
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