Battery state detection method during charging process, battery charging circuit and charger

Abstract

The application relates to a battery state detection method in a charging process, a battery charging circuit and a charger. The battery charging circuit comprises a voltage conversion module and a primary side control module. In the battery charging process, the primary side control module performs the following steps: sampling the output voltage of the auxiliary winding of the primary side of the voltage conversion module according to a switching period to obtain the voltage information of the secondary side; saving the obtained voltage information of the secondary side according to a preset sampling period, then processing the voltage information of the secondary side according to a preset comparison period to obtain the voltage variation trend of the output end of the battery charging circuit; and detecting the battery state of the output end of the battery charging circuit according to the voltage variation trend. The primary side control module can be used to monitor the battery state in the charging process in real time, the detection circuit and the feedback circuit do not need to be additionally arranged, the complexity of the circuit is simplified, the product cost is reduced, the conversion circuit has no influence, and the reliability is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery charging, and more particularly to a battery state detection method in a charging process, a battery charging circuit and a charger. BACKGROUND

[0002] In a battery charging process, in order to ensure the charging safety of the battery load, the state of the battery load at the output end of the charging circuit needs to be monitored in real time. The commonly used method is to set a detection circuit on the secondary side of the charging circuit, and cooperate with a corresponding feedback circuit (such as an optical coupler), to feed back the battery information detected by the detection circuit to the primary side through the feedback circuit, and then determine the state of the battery load according to the feedback battery information on the primary side.

[0003] The current detection method needs to additionally set a detection circuit and a feedback circuit, which increases the complexity of the circuit and also increases the cost. In addition, since the detection is performed by the detection circuit on the secondary side, the output voltage or current on the secondary side is obtained by converting and outputting by the energy conversion circuit after being adjusted and controlled by the control circuit on the primary side, therefore, the information detected on the secondary side will be affected by the control circuit and the energy conversion circuit, and thus the reliability of the detection is reduced. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a battery state detection method in a charging process, a battery charging circuit and a charger.

[0005] The technical solution adopted by the present application to solve the technical problem is: a battery state detection method in a charging process is constructed, which is applied to a battery charging circuit, the battery charging circuit comprises: a voltage conversion module for converting the energy on the primary side and transmitting it to the secondary side, and a primary side control module connected with the voltage conversion module, in the battery charging process, the primary side control module performs the following steps:

[0006] According to the switching frequency, the output voltage of the auxiliary winding on the primary side of the voltage conversion module is sampled to obtain the instantaneous voltage information on the secondary side;

[0007] According to a preset sampling period, the instantaneous voltage information on the secondary side is maintained;

[0008] According to a preset determination period, the instantaneous voltage information on the secondary side and the voltage information maintained at the previous moment are processed to obtain the voltage variation trend of the output end of the battery charging circuit;

[0009] According to the voltage variation trend, the state of the battery at the output end of the battery charging circuit is detected.

[0010] In the battery state detection method during the charging process described in this invention, the voltage change trend includes: rapid increase, slow increase, unchanged, rapid decrease, slow decrease, and repeated fluctuation.

[0011] In the battery state detection method during charging according to the present invention, the primary-side control module detects the battery state at the output terminal of the battery charging circuit based on the voltage change trend, including:

[0012] The voltage change trend is compared with the current charging state of the primary-side control module;

[0013] Determine whether the voltage change trend matches the current charging state of the primary-side control module;

[0014] If a match is found, the battery status at the output of the battery charging circuit is determined to be normal.

[0015] If there is a mismatch, the battery status at the output of the battery charging circuit is determined to be abnormal.

[0016] In the battery state detection method during charging according to the present invention, the primary-side control module includes: a primary-side control chip; the primary-side control chip includes: a voltage sampling and holding circuit, a voltage holding circuit, a comparator, a timer, and a clock control circuit;

[0017] The voltage sample and hold circuit samples the output voltage of the auxiliary winding on the primary side of the voltage converter according to the switching frequency to obtain the instantaneous voltage information on the secondary side.

[0018] The voltage holding circuit samples and holds the instantaneous voltage information on the secondary side according to the preset sampling period;

[0019] The comparison circuit, based on the control of the clock control circuit, processes the instantaneous voltage information of the secondary side output by the voltage sampling and holding circuit and the voltage information held at the previous moment output by the voltage holding circuit according to the preset judgment period, so as to obtain the voltage change trend at the output of the battery charging circuit.

[0020] The timer filters out interference noise from the comparison circuit.

[0021] The present invention also provides a battery charging circuit, comprising: a voltage conversion module for converting energy on the primary side and transferring it to the secondary side, and a primary-side control module connected to the voltage conversion module. During battery charging, the primary-side control module executes the battery state detection method described above.

[0022] The primary side control module comprises an output voltage sampling circuit and a primary side control chip.

[0023] An input end of the output voltage sampling circuit is connected to an output end of the auxiliary winding of the primary side of the voltage conversion module, and an output end of the output voltage sampling circuit is connected to a voltage feedback pin of the primary side control chip.

[0024] The output voltage sampling circuit samples the output voltage of the auxiliary winding of the primary side of the voltage conversion module to obtain the voltage information of the secondary side.

[0025] The primary side control chip is configured to:

[0026] The output voltage of the auxiliary winding of the primary side of the voltage conversion module is sampled according to the switching frequency to obtain the instantaneous voltage information of the secondary side.

[0027] The instantaneous voltage information of the secondary side is sampled and held according to a preset sampling period.

[0028] The instantaneous voltage information of the secondary side and the voltage information held at a previous moment are processed according to a preset determination period to obtain the voltage variation trend of the output end of the battery charging circuit.

[0029] The battery state of the output end of the battery charging circuit is detected according to the voltage variation trend.

[0030] In the battery charging circuit, the voltage variation trend comprises rapid rise, slow rise, constant, rapid decline, slow decline and repeated fluctuation.

[0031] In the battery charging circuit, the voltage holding circuit comprises a first holding circuit and a second holding circuit, and the preset sampling period comprises a first sampling period and a second sampling period.

[0032] The first holding circuit samples and holds the instantaneous voltage information of the secondary side according to the first sampling period.

[0033] The second holding circuit samples and holds the instantaneous voltage information of the secondary side according to the second sampling period.

[0034] In the battery charging circuit, the comparison circuit comprises a first comparator and a second comparator.

[0035] The first input end of the first comparator is connected with the output end of the first holding circuit, and the second input end of the first comparator is connected with the output end of the voltage sampling holding circuit; the first comparator controls whether to output a comparison signal according to a first determination period output by the clock control circuit;

[0036] The first input end of the second comparator is connected with the output end of the second holding circuit, and the second input end of the second comparator is connected with the output end of the voltage sampling holding circuit; the second comparator controls whether to output a comparison signal according to a second determination period output by the clock control circuit.

[0037] The application further provides a charger comprising the battery charging circuit.

[0038] The battery state detection method, the battery charging circuit and the charger in the charging process have the following beneficial effects: in the charging process of the battery, the primary side control module performs the following steps: sampling the output voltage of the auxiliary winding of the voltage conversion module on the primary side according to a preset sampling period to obtain voltage information of the secondary side; processing the voltage information of the secondary side to obtain a voltage variation trend of the output end of the battery charging circuit; and detecting the battery state of the output end of the battery charging circuit according to the voltage variation trend. The primary side control module can monitor the battery state in real time in the charging process, without the need of setting an additional detection circuit and a feedback circuit, so that the complexity of the circuit is simplified, the product cost is reduced, and the reliability is high. BRIEF DESCRIPTION OF DRAWINGS

[0039] The application will be further described below in combination with the drawings and examples, and the drawings are as follows:

[0040] Figure 1 is a flowchart of the battery state detection method in the charging process provided by the application;

[0041] Figure 2 is a circuit diagram of the battery charging circuit provided by the application;

[0042] Figure 3 is a schematic diagram of the internal structure of the primary side control chip provided by the application;

[0043] Figure 4 is a timing diagram of the battery state detection provided by the application;

[0044] Figure 5 is a schematic diagram of the structure of the comparison circuit provided by the application;

[0045] Figure 6 is a schematic diagram of the structure of the voltage holding circuit provided by the application. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0047] With reference to Figure 1 , the present application provides a battery state detection method in a charging process. The method can realize acquisition of voltage information of a secondary side through a primary side control module 20, and obtain a voltage variation trend of an output end according to the voltage information of the secondary side, and then realize detection of a battery state according to the voltage variation trend of the output end. The method does not need to additionally add a load detection circuit and an optical coupling isolation feedback circuit, can simplify a circuit structure and reduce product cost under the condition of ensuring accurate detection of the battery state, and can also improve reliability and accuracy of monitoring.

[0048] Specifically, the battery state detection method in the charging process is realized through a battery charging circuit in the embodiment. Figure 2 As shown in Figure 2 , the battery charging circuit includes a voltage conversion module 30 for converting energy of a primary side and transmitting the energy to a secondary side, and a primary side control module 20 connected with the voltage conversion module 30.

[0049] As shown in Figure 2 , the voltage conversion module 30 in the embodiment includes a primary side original winding, a secondary side auxiliary winding, and a primary side auxiliary winding. The original winding, the auxiliary winding, and the auxiliary winding are all wound on the same core to form a high-frequency isolation transformer. The high-frequency isolation transformer converts and transmits energy of the primary side to the secondary side according to a driving action of the primary side control module 20, and outputs to a positive output end after rectification and filtering processing by an output module 40 of the secondary side.

[0050] As shown in Figure 2 , the primary side control module 20 includes an output voltage sampling circuit 205 and a primary side control chip 201.

[0051] The input end of the output voltage sampling circuit 205 is connected with the output end of the auxiliary winding of the primary side of the voltage conversion module 30, and the output end of the output voltage sampling circuit 205 is connected with the voltage feedback pin of the primary side control chip 201; the output voltage sampling circuit 205 samples the output voltage of the auxiliary winding of the primary side of the voltage conversion module 30 to obtain the voltage information of the secondary side; the primary side control chip 201 samples the output voltage of the auxiliary winding of the primary side of the voltage conversion module according to the switching frequency to obtain the instantaneous voltage information of the secondary side; the instantaneous voltage information of the secondary side is kept according to a preset sampling period; the instantaneous voltage information of the secondary side and the voltage information kept at the previous moment are processed according to a preset judgment period to obtain the voltage variation trend of the output end of the battery charging circuit; and the state of the battery at the output end of the battery charging circuit is detected according to the voltage variation trend.

[0052] Further, as shown in the figure, the primary side control module 20 further comprises a driving circuit 206 connected with the control chip and the voltage conversion module 30 respectively. Figure 2

[0053] The driving circuit 206 adjusts the primary winding of the voltage conversion module 30 according to the driving control signal output by the primary side control chip 201 to control the voltage conversion module 30 to convert the direct current voltage; and the output voltage sampling circuit 205 samples the auxiliary winding voltage of the voltage conversion module 30 and outputs the voltage information of the secondary side to the primary side control chip 201.

[0054] Further, as shown in the figure, Figure 2 The primary side control module 20 further comprises an input voltage sampling circuit 202, a chip power supply circuit 203 and a spike absorption circuit 204.

[0055] The input voltage sampling circuit 202 is connected between the output end of the input module 10 and the second pin of the primary side control chip 201; the first end of the chip power supply circuit 203 is connected with the output end of the input module 10, the second end of the chip power supply circuit 203 is connected with the first pin of the primary side control chip 201, and the third end of the chip power supply circuit 203 is connected with the voltage conversion module 30; the first end of the spike absorption circuit 204 is connected with the output end of the input module 10, and the second end of the spike absorption circuit 204 is connected with the voltage conversion module 30.

[0056] As shown in the figure, Figure 2 The input module 10 comprises a rectifier bridge BD and a first capacitor C1 connected with two output ends of the rectifier bridge BD. The first capacitor C1 is a polar capacitor, the positive pole of which is the output end of the input module 10, and the negative pole of which is grounded. The rectifier bridge BD is preferably a full-bridge rectifier bridge, and the first capacitor C1 is an input filter capacitor.

[0057] ​The input voltage sampling circuit 202 comprises a first resistor R1 and a second resistor R2; the chip power supply circuit 203 comprises a third resistor R3, a second capacitor C2, a fifth resistor R5 and a first diode D1; and the spike absorption circuit 204 comprises a fourth capacitor C4, a sixth resistor R6 and a second diode D2.

[0058] The first end of the first resistor R1 is connected to the output end of the input module 10, the second end of the first resistor R1 is connected to the second pin of the primary side control chip 201 and the first end of the second resistor R2, and the second end of the second resistor R2 is grounded; the first end of the third resistor R3 is connected to the first end of the fifth resistor R5, the first pin of the primary side control chip 201 and the first end of the second capacitor C2, the second end of the second capacitor C2 is grounded, the second end of the fifth resistor R5 is connected to the cathode of the first diode D1, and the anode of the first diode D1 is connected to the opposite name end of the auxiliary winding of the voltage conversion module 30; the first end of the fourth capacitor C4 is connected to the output end of the input module 10, the second end of the fourth capacitor C4 is connected to the cathode of the second diode D2, the anode of the second diode D2 is connected to the opposite name end of the primary winding of the voltage conversion module 30, and the sixth resistor R6 is connected in parallel with the fourth capacitor C4.

[0059] As shown in Figure 2 , the input voltage sampling circuit 202 receives the direct current voltage output by the input module 10, and obtains an input sampling signal by dividing the voltage through the first resistor R1 and the second resistor R2, and inputs the input sampling signal to the second pin (i.e. the overvoltage detection pin OVP) of the primary side control chip 201, and compares the voltage value of the input sampling signal with the reference voltage set in the primary side control chip 201, so as to achieve the purpose of monitoring whether the direct current voltage output by the input module 10 is abnormal (such as overvoltage abnormality or undervoltage abnormality), and if abnormal, the primary side control chip 201 stops working until the abnormality is eliminated and then resumes working, so as to achieve the purpose of protecting the primary side control chip 201 and avoiding damage to the primary side control chip 201.

[0060] As shown in Figure 2 , the chip power supply circuit 203 receives the direct current voltage output by the input module 10 and generates a corresponding starting voltage to the first pin (VCC power supply pin) of the primary side control chip 2011, and after the primary side control chip 201 is started, rectifies the voltage output by the auxiliary winding through the first diode D1 and outputs a stable working voltage to the first pin of the primary side control chip 201, so as to realize stable power supply to the primary side control chip 201 and ensure normal and stable working of the primary side control chip 201. As shown in Figure 2 , the starting voltage is provided by the third resistor R3 and the second capacitor C2, and the stable working voltage is provided by the fifth resistor R5 and the first diode D1.

[0061] AsFigure 2 As shown in the embodiment, the output voltage sampling circuit 205 includes a first sampling resistor FB1 and a second sampling resistor FB2; and the driving circuit 206 includes a switch tube Q1, a seventh resistor R7 and an eighth resistor R8.

[0062] The first end of the first sampling resistor FB1 is connected to the output end of the auxiliary winding of the primary side of the voltage conversion module 30, the second end of the first sampling resistor FB1 is connected to the first end of the second sampling resistor FB2 and the voltage feedback pin of the primary side control chip 201, and the second end of the second sampling resistor FB2 is grounded; the control end of the switch tube Q1 is connected to the seventh pin of the primary side control chip 201, the input end of the switch tube Q1 is connected to the opposite-phase end of the primary winding of the voltage conversion module 30, the output end of the switch tube Q1 is grounded through the eighth resistor R8, and the first end of the seventh resistor R7 is connected to the control end of the switch tube Q1, and the second end of the seventh resistor R7 is grounded.

[0063] As shown in the embodiment, Figure 2 Since the transformer is a flyback winding transformer, the number of turns of the primary winding is Np, the number of turns of the secondary winding is Ns, and the number of turns of the auxiliary winding is Nf, the voltage at point C can be obtained by the formula: V C = V A *Nf / Ns, therefore, the voltage detection signal received by the eighth pin of the primary side control chip 201 can be obtained by dividing the voltage at point C through the first sampling resistor FB1 and the second sampling resistor FB2. Therefore, the voltage information at point A can be monitored by monitoring the voltage at point C.

[0064] As shown in the embodiment, Figure 2 The output module 40 includes a third diode D3, a fifteenth capacitor C15 and a fifteenth resistor R15.

[0065] The anode of the third diode D3 is connected to the output end of the voltage conversion module 30 (i.e., the anode of the third diode D3 is connected to the opposite-phase end of the secondary winding), the cathode of the third diode D3 is connected to the first end of the fifteenth capacitor C15, the second end of the fifteenth resistor R15 is grounded, and the fifteenth resistor R15 is connected in parallel with the fifteenth capacitor C15; the cathode of the third diode D3 is also connected to the positive output end. The high-frequency pulse output by the secondary winding is rectified by the third diode D3 to obtain a voltage signal (the voltage signal is direct current), and then the voltage signal is filtered by the fifteenth capacitor C15 to obtain a stable output voltage. At the same time, the fifteenth capacitor C15 also stores energy during the filtering process and discharges through the fifteenth resistor R15 after the battery is removed.

[0066] As shown in the embodiment, Figure 3As shown in the figure, it is an internal structure diagram of the primary side control chip 201 provided in the embodiment. In the embodiment, the primary side control chip 201 includes: a voltage sampling and holding circuit 211, a voltage holding circuit 212, a clock control circuit 213, a comparison circuit 214 and a timer 215.

[0067] The input end of the voltage sampling and holding circuit 211 is connected to the eighth pin of the primary side control chip 201, the output end of the voltage sampling and holding circuit 211 is connected to the input end of the voltage holding circuit 212 and the second input end of the comparator 214, the output end of the voltage holding circuit 212 is connected to the first input end of the comparison circuit 214, the clock control circuit 213 is connected to the comparison circuit 214 and the voltage holding circuit 212 respectively, and the output end of the comparison circuit 214 is connected to the timer 215.

[0068] The voltage sampling and holding circuit 211 samples the output voltage of the auxiliary winding of the primary side of the voltage conversion according to the switching frequency, and obtains the instantaneous voltage information of the secondary side; the voltage holding circuit 212 samples and holds the instantaneous voltage information of the secondary side according to a preset sampling period; the comparison circuit 214 processes the instantaneous voltage information of the secondary side output by the voltage sampling and holding circuit 211 and the voltage information held at the previous moment output by the voltage holding circuit 212 according to a preset judgment period based on the control of the clock control circuit 213, and obtains the voltage variation trend of the output end of the battery charging circuit; and the timer 215 filters the interference noise of the comparison circuit, so as to ensure the stability of the signal output by the comparison circuit 214 and avoid the triggering of glitches or false signals.

[0069] As shown in the figure, Figure 2 the voltage information of the secondary side can be monitored by monitoring the voltage of the C point, without the need of additionally adding a battery load detection circuit at the output end or additionally adding an isolation optocoupler feedback circuit. The battery state detection during the charging process can be realized by the battery state detection method during the charging process provided in the embodiment, and the battery state detection method during the charging process can be realized based on the battery charging circuit shown in the figure. Figure 2

[0070] As shown in the figures, Figure 5 and Figure 6 the voltage holding circuit 212 includes: a first holding circuit 2121 and a second holding circuit 2122. The preset sampling period includes: a first sampling period and a second sampling period.

[0071] ​The first holding circuit 2121 samples and holds the instantaneous voltage information of the secondary side according to a first sampling period; and the second holding circuit 2122 samples and holds the instantaneous voltage information of the secondary side according to a second sampling period. By comparing the instantaneous voltage information output by the first holding circuit 2121, the voltage change trend of fast change (such as rapid rise or rapid fall) or slow change (such as slow rise or slow fall) can be obtained. Similarly, by comparing the instantaneous voltage information output by the second holding circuit 2122, the voltage change trend of fast change (such as rapid rise or rapid fall) or slow change (such as slow rise or slow fall) can be obtained. In actual application, the sampling periods of the first holding circuit 2121 and the second holding circuit 2122 can be set as needed, and the present application is not limited in this regard.

[0072] As shown in Figure 5 , the comparison circuit 214 includes a first comparator 2141 and a second comparator 2142.

[0073] The first input end of the first comparator 2141 is connected to the output end of the first holding circuit 2121, and the second input end of the first comparator 2141 is connected to the output end of the voltage sampling and holding circuit 211; the first comparator 2141 controls whether to output a comparison signal according to the first determination period output by the clock control circuit 213; the first input end of the second comparator 2142 is connected to the output end of the second holding circuit 2122, and the second input end of the second comparator 2142 is connected to the output end of the voltage sampling and holding circuit 211; the second comparator 2142 controls whether to output a comparison signal according to the second determination period output by the clock control circuit 213.

[0074] Specifically, as shown in Figure 1 , during the battery charging process, the following steps are performed by the primary side control module 20:

[0075] Step S10: sampling the output voltage of the auxiliary winding of the voltage conversion module 30 on the primary side according to the switching frequency, to obtain the instantaneous voltage information of the secondary side.

[0076] The voltage information of the secondary side is the voltage information of point C in Figure 2 .

[0077] Specifically, as previously known, the voltage information of point C can be divided by the first sampling resistor FB1 and the second sampling resistor FB2, and then transmitted to the voltage feedback pin (i.e. the eighth pin) of the primary side control chip 201.

[0078] Step S20: holding the instantaneous voltage information of the secondary side according to a preset sampling period.

[0079] Step S30, according to the preset determination period, the transient voltage information of the secondary side and the voltage information maintained at the previous time are processed to obtain the voltage variation trend of the output end of the battery charging circuit.

[0080] In this embodiment, the voltage variation trend includes: rapid rise, slow rise, keep unchanged, rapid decline, slow decline and repeated fluctuation.

[0081] It should be noted that, in the embodiment of the application, the output voltage of the auxiliary winding of the primary side of the voltage conversion module 30 is sampled according to the preset sampling period, and the voltage information of the secondary side is obtained, so the voltage variation trend of the output end of the battery charging circuit is a dynamic monitoring process, that is, it is detected once every preset sampling period, so the preset time period of the embodiment of the application is repeated once every preset sampling period.

[0082] As shown in Figure 3 , the voltage information of the secondary side (that is, the voltage of the C point) is obtained through the FB pin (voltage feedback pin) of the primary side control chip 201, and then the voltage of the C point is maintained through the voltage maintaining circuit 212 according to the preset sampling period (set as T) to generate the N point voltage signal (which is the first voltage signal), then every time T1 (that is, at the second collection time of the preset sampling period), the C point voltage information of the voltage sampling maintaining circuit 211 is obtained, that is, the second voltage signal (that is, the voltage of the M point), the second voltage signal is compared with the first voltage signal to obtain the voltage variation trend of the secondary side.

[0083] Wherein, the rapid rise refers to the rising amount of the difference between the voltage of the M point and the voltage of the N point within the preset time is greater than the rapid rise amount.

[0084] Slow rise refers to the rising amount of the difference between the voltage of the M point and the voltage of the N point within the preset time is less than the slow rise amount.

[0085] Rapid decline refers to the falling amount of the difference between the voltage of the M point and the voltage of the N point within the preset time is greater than the rapid decline amount.

[0086] Slow decline refers to the falling amount of the difference between the voltage of the M point and the voltage of the N point within the preset time is greater than the slow decline amount.

[0087] Keep unchanged refers to the difference between the voltage of the M point and the voltage of the N point is less than the threshold value.

[0088] Repeated fluctuation refers to the difference between the voltage of the M point and the voltage of the N point is within the preset range and is changing.

[0089] It can be understood that in other embodiments, the determination of the rapid rise, slow rise, keep unchanged, rapid decline, slow decline and repeated fluctuations can also be made in other ways, not limited to the above ways.

[0090] In step S40, the battery state at the output end of the battery charging circuit is detected according to the voltage change trend.

[0091] In this embodiment, the battery state at the output end of the battery charging circuit detected by the primary side control module 20 according to the voltage change trend includes: if the voltage change trend is the first change trend, the primary side control module 20 determines that the battery at the output end is damaged or the user is improperly operating the battery; if the voltage change trend is the second change trend, the primary side control module 20 determines that the battery at the output end is faulty.

[0092] Specifically, as shown in Figure 3 The primary side control chip 201 monitors the voltage at point A through its FB pin, monitors the voltage signal at point C through the voltage holding circuit 212 every time interval T, generates the N point signal, enables the comparison circuit 214 every time interval T1, and compares the voltage at point M with the voltage at point N through the comparison circuit 214 to obtain the voltage change trend at the output end. Figure 4 As shown in At the first comparison, the voltage change trend from time t2 to time t3 is a downward trend, and the voltage at time t2 is V2 and the voltage at time t3 is V3. Comparing V3 and V2 can obtain that V3 is less than V2, at this time, it can be determined that the voltage at point A is a downward trend. Specifically, first, comparing V3 and V2 can obtain that V2 is less than V2, then it can be determined that the voltage at point A is a downward trend, then the slope calculation is performed, that is, k = |(V3-V2)| / (t3-t2), then k and k01 (preset slope of rapid decline) and k02 (preset slope of slow decline) are compared, if k is greater than k01, it can be determined that the voltage change trend is rapid decline, and if k is less than k02, it is determined that the voltage change trend is slow decline.

[0093] Figure 4As shown in the figure, the comparison circuit 214 is enabled again at the time t5 and t6 to compare the voltage change trend, wherein the voltage at the time t5 is V5, and the voltage at the time t6 is V6, and the comparison between V6 and V5 can obtain that V6 is greater than V5, at this time, it can be determined that the voltage at point A is in an upward trend. Specifically, first, the comparison between V6 and V5 can obtain that V6 is greater than V5, and then it can be determined that the voltage at point A is in an upward trend, and then the slope calculation is performed, that is, k = |(V6-V5)| / (t6-t5), and then the comparison between k and k0 (the preset slope of the rapid rise) and k1 (the preset slope of the slow rise) is performed, if k is greater than k0, it can be determined that the voltage change trend is a rapid rise, and if k is less than k1, it can be determined that the voltage change trend is a slow rise.

[0094] In the embodiment of the present application, the preset sampling period and the preset determination period can be determined according to actual use, and the present application is not limited specifically.

[0095] Further, in this step, the battery state of the output end of the battery charging circuit is detected according to the voltage change trend by the primary side control module 20, including: comparing the voltage change trend with the current charging state of the primary side control module 20; determining whether the voltage change trend matches the current charging state of the primary side control module 20; if it matches, it is determined that the battery state of the output end of the battery charging circuit is normal; if it does not match, it is determined that the battery state of the output end of the battery charging circuit is abnormal.

[0096] Further, the embodiment of the present application further includes the following steps after step S40:

[0097] Step S50: performing corresponding processing according to the battery state detection result.

[0098] Specifically, the corresponding processing according to the battery state detection result can be: if the battery state of the output end is detected to be abnormal, an alarm signal of the abnormal battery state is output. The alarm signal of the abnormal battery state can be realized in different ways. For example, it can be realized in the way of flashing light (for example, the alarm signal of the damaged battery can be realized in the way of red light flashing, and the alarm signal of the battery failure can be realized in the way of yellow light flashing), or it can be realized in the way of buzzer alarm (for example, the alarm signal of the damaged battery can be realized in the way of long buzzing of the buzzer, and the alarm signal of the battery failure can be realized in the way of interval short buzzing of the buzzer), or it can also be realized in the way of direct display.

[0099] Alternatively, if the battery state is detected to be abnormal, the primary side control module 20 can directly stop working to ensure the safety of the battery and the battery charging circuit.

[0100] Further, the application also provides a charger, and the battery charging circuit disclosed by the embodiment of the application. The charger can realize real-time monitoring of the state of the battery load at the output end during the charging process based on the battery state detection method during the charging process disclosed by the embodiment of the application, does not need to additionally set a detection circuit and a feedback circuit, simplifies the complexity of the circuit, reduces the product cost, is not affected by the conversion circuit, and has high reliability. In addition, the application can also output an alarm signal, timely remind the user, avoid further damage to the battery, reduce the risk, and improve the charging safety.

[0101] The various embodiments are described in a progressive manner in the specification, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed by the embodiment, since it corresponds to the method disclosed by the embodiment, the description is relatively simple, and the related parts can be referred to the method part.

[0102] The skilled person can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in the present text can be realized in electronic hardware, computer software or combination of both, and in order to clearly show the interchangeability of hardware and software, the composition and steps of each example have been described in the above description. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0103] The steps of the method or algorithm described in combination with the embodiments disclosed in the present text can be directly implemented in hardware, software modules executed by a processor, or a combination of both. The software modules can be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0104] The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it accordingly, and cannot limit the protection scope of the present application. Any equivalent changes and modifications made within the scope of the claims of the present application shall belong to the scope of the claims of the present application.

Claims

1. A method for detecting a state of a battery during charging, applied to a battery charging circuit, characterized in that, The battery charging circuit comprises a voltage conversion module for converting and transmitting the energy of the primary side to the secondary side and a primary side control module connected with the voltage conversion module, wherein during the battery charging process, the primary side control module performs the following steps: According to the switching frequency, the output voltage of the auxiliary winding of the primary side of the voltage conversion module is sampled to obtain the instantaneous voltage information of the secondary side; According to a preset sampling period, the instantaneous voltage information of the secondary side is maintained; According to a preset determination period, the instantaneous voltage information of the secondary side and the voltage information maintained at the previous time are processed to obtain the voltage variation trend of the output end of the battery charging circuit; According to the voltage variation trend, the battery state of the output end of the battery charging circuit is detected; the primary side control module detects the battery state of the output end of the battery charging circuit according to the voltage variation trend, which comprises: comparing the voltage variation trend with the current charging state of the primary side control module; determining whether the voltage variation trend matches the current charging state of the primary side control module; if yes, it is determined that the battery state of the output end of the battery charging circuit is normal; if no, it is determined that the battery state of the output end of the battery charging circuit is abnormal.

2. The method according to claim 1, wherein The voltage variation trend comprises: rapid rise, slow rise, constant, rapid drop, slow drop and repeated fluctuation.

3. The method of claim 1, wherein The primary side control module comprises a primary side control chip; the primary side control chip comprises a voltage sampling and maintaining circuit, a voltage maintaining circuit, a comparison circuit, a timer and a clock control circuit; The voltage sampling and maintaining circuit samples the output voltage of the auxiliary winding of the primary side of the voltage conversion to obtain the instantaneous voltage information of the secondary side according to the switching frequency; The voltage maintaining circuit samples and maintains the instantaneous voltage information of the secondary side according to the preset sampling period; The comparison circuit processes the instantaneous voltage information of the secondary side output by the voltage sampling and maintaining circuit and the voltage information maintained at the previous time output by the voltage maintaining circuit according to the preset determination period based on the control of the clock control circuit to obtain the voltage variation trend of the output end of the battery charging circuit; The timer filters the interference noise of the comparison circuit.

4. A battery charging circuit, characterized by, Comprise: The battery charging circuit comprises a voltage conversion module for converting and transmitting the energy of the primary side to the secondary side and a primary side control module connected with the voltage conversion module, wherein during the battery charging process, the primary side control module performs the charging process and battery state detection method of claim 3.

5. The battery charging circuit of claim 4, wherein, The primary side control module comprises an output voltage sampling circuit and a primary side control chip; The input end of the output voltage sampling circuit is connected with the output end of the auxiliary winding of the primary side of the voltage conversion module, and the output end of the output voltage sampling circuit is connected with the voltage feedback pin of the primary side control chip; The output voltage sampling circuit samples the output voltage of the auxiliary winding of the primary side of the voltage conversion module to obtain the voltage information of the secondary side; The primary side control chip is used for: According to the switching frequency, the output voltage of the auxiliary winding of the primary side of the voltage conversion module is sampled to obtain the instantaneous voltage information of the secondary side; According to a preset sampling period, the instantaneous voltage information of the secondary side is sampled and held; According to a preset determination period, the instantaneous voltage information of the secondary side and the voltage information held at a previous time are processed to obtain the voltage variation trend of the output end of the battery charging circuit; According to the voltage variation trend, the state of the battery at the output end of the battery charging circuit is detected.

6. The battery charging circuit of claim 5, wherein, The voltage variation trend includes rapid rise, slow rise, constant, rapid decline, slow decline, and repeated fluctuation.

7. The battery charging circuit of claim 5, wherein, The voltage holding circuit includes a first holding circuit and a second holding circuit; the preset sampling period includes a first sampling period and a second sampling period; The first holding circuit samples and holds the instantaneous voltage information of the secondary side according to the first sampling period; The second holding circuit samples and holds the instantaneous voltage information of the secondary side according to the second sampling period.

8. The battery charging circuit of claim 7, wherein, The comparison circuit includes a first comparator and a second comparator; The first input end of the first comparator is connected to the output end of the first holding circuit, the second input end of the first comparator is connected to the output end of the voltage sampling and holding circuit; the first comparator controls whether to output a comparison signal according to the first determination period output by the clock control circuit; The first input end of the first comparator is connected to the output end of the first holding circuit, the second input end of the first comparator is connected to the output end of the voltage sampling and holding circuit; the first comparator controls whether to output a comparison signal according to the first determination period output by the clock control circuit; 9. A charger characterized by comprising: The battery charging circuit includes any one of claims 4-8. The battery charging circuit includes any one of claims 4-8.

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