Controller with variable x-capacitor discharging mechanism and related operational method

Abstract

A controller with a variable X-capacitor discharge mechanism includes a voltage detection circuit and a discharge circuit, wherein the controller is applied to a power converter and the X-capacitor is coupled to the power converter. The voltage detection circuit receives a detection voltage through a pin of the controller and determines whether a discharge signal is generated based on changes in the detection voltage. The detection voltage is generated by an input voltage, either an AC or DC input voltage, to the power converter, and the discharge signal lasts for a predetermined time. The discharge circuit is coupled to the voltage detection circuit and the pin, and discharges the X-capacitor according to the discharge signal.

Description

[Technical Field]

[0001] This invention relates to a controller with an X-capacitor discharge mechanism and a related operating method, and more particularly to a controller with a variable X-capacitor discharge mechanism and a related operating method. [Previous Technology]

[0002] In the prior art, the common X capacitor discharge mechanism is that when the detected voltage has a continuous periodic change, the controller treats the input voltage to the power converter as an AC voltage and does not actively discharge the X capacitor; once the voltage source providing the input voltage is removed, the detected voltage of the X capacitor no longer has a periodic change (that is, when the voltage source providing the input voltage is removed, there is a residual voltage on the X capacitor, and the residual voltage does not have a continuous periodic change), causing the controller to actively discharge the X capacitor to release the residual voltage and meet the requirements of safety specifications.

[0003] However, if the input voltage is a DC voltage, because the detected voltage does not have a continuous periodic change, the controller will continuously discharge the X capacitor, which can easily cause damage to the controller and the risk of overheating. Therefore, how to design a controller with a variable X capacitor discharge mechanism has become an important issue for the designers of this controller. [Summary of the Invention]

[0004] An embodiment of the present invention provides a controller with a variable X-capacitor discharge mechanism, wherein the controller is applied to a power converter and the X-capacitor is coupled to the power converter, and the controller includes a voltage detection circuit and a discharge circuit. The voltage detection circuit is used to receive a detection voltage through a pin of the controller, and to determine whether a discharge signal is generated based on the change of the detection voltage, wherein the detection voltage is generated by an input voltage input to the power converter, the input voltage being an AC input voltage or a DC input voltage, and the discharge signal lasting for a predetermined time; and the discharge circuit is coupled to the voltage detection circuit and the pin, and is used to discharge the X-capacitor according to the discharge signal.

[0005] In one embodiment of the present invention, the pin is coupled to both ends of the X capacitor, and the X capacitor is coupled to a bridge rectifier included in the power converter.

[0006] In one embodiment of the present invention, when the input voltage is the AC input voltage and the detection voltage does not change periodically in a first predetermined time, the voltage detection circuit generates the discharge signal after the first predetermined time, and the discharge circuit discharges the X capacitor through a discharge current and the pin, wherein the predetermined time is greater than the first predetermined time.

[0007] In one embodiment of the present invention, during the first predetermined time, the controller activates a capacitor discharge detection, a brown-out protection detection, and an overload protection detection.

[0008] In one embodiment of the present invention, during the predetermined time, the controller turns off the low voltage protection detection and the overload protection detection. After the predetermined time ends, the controller turns on the low voltage protection detection and turns off the X capacitor discharge detection. After the controller turns on the low voltage protection detection again, and after a second predetermined time when the detection voltage is less than a first reference voltage, the controller turns on a low voltage protection. The first reference voltage is related to the low voltage protection detection.

[0009] In one embodiment of the present invention, when the input voltage is the DC input voltage and the detection voltage is a certain value in a first predetermined time, the voltage detection circuit generates the discharge signal after the first predetermined time, and the discharge circuit discharges the X capacitor through a discharge current and the pin, wherein the predetermined time is greater than the first predetermined time.

[0010] In one embodiment of the present invention, during the first predetermined time, the controller activates a capacitor discharge detection, a low voltage protection detection and an overload protection detection.

[0011] In one embodiment of the present invention, during the predetermined time, the controller turns off the low voltage protection detection and the overload protection detection. After the predetermined time ends, the controller turns on the low voltage protection detection and turns off the X capacitor discharge detection. After the controller turns on the low voltage protection detection again, and after a second predetermined time when the detection voltage is less than a first reference voltage, the controller turns on a low voltage protection. The first reference voltage is related to the low voltage protection detection.

[0012] In one embodiment of the present invention, during the predetermined time, the controller turns off the low voltage protection detection and the overload protection detection, and after the predetermined time ends, the controller turns on the low voltage protection detection and turns off the X capacitor discharge detection, wherein during the predetermined time, the detection voltage is greater than a first reference voltage.

[0013] In one embodiment of the present invention, after the predetermined time ends, at a third predetermined time, when the detected voltage is the set value and is greater than a second reference voltage, the controller restarts the overload protection detection, wherein the second reference voltage is related to the overload protection detection.

[0014] In one embodiment of the present invention, the voltage detection circuit generates multiple detection signals according to the periodic change of the detection voltage, and when no detection signal is generated within a fourth predetermined time after the voltage detection circuit generates the multiple detection signals, the voltage detection circuit generates the discharge signal after the fourth predetermined time.

[0015] In one embodiment of the present invention, when the detection voltage reaches a peak value and is less than a detection reference voltage, the voltage detection circuit generates a detection signal.

[0016] In one embodiment of the present invention, when a voltage source provides an input voltage to the power converter for a fifth predetermined time after the power converter is turned on and the voltage detection circuit does not generate a detection signal during the fifth predetermined time, the voltage detection circuit does not generate the discharge signal after the fifth predetermined time.

[0017] In one embodiment of the present invention, the pin is coupled to the output terminal of a bridge rectifier included in the power converter, and the X capacitor is coupled to the bridge rectifier.

[0018] In one embodiment of the present invention, when the input voltage is the AC input voltage and the detection voltage is a certain value for a first predetermined time, the controller turns off an X capacitor discharge detection and continuously turns on a low voltage protection detection and an overload protection detection, wherein the set value is greater than a first reference voltage and a second reference voltage, the first reference voltage is related to the low voltage protection detection, and the second reference voltage is related to the overload protection detection.

[0019] In one embodiment of the present invention, when the input voltage is the DC input voltage and the detection voltage is a certain value for a first predetermined time, the controller turns off a capacitor discharge detection and keeps on a low voltage protection detection and an overload protection detection, wherein the set value is greater than a first reference voltage and a second reference voltage, the first reference voltage is related to the low voltage protection detection, and the second reference voltage is related to the overload protection detection.

[0020] Another embodiment of the present invention provides an operating method for a controller with a variable X-capacitor discharge mechanism, wherein the controller is applied to a power converter, the X-capacitor is coupled to the power converter, and the controller includes a voltage detection circuit and a discharge circuit. The operating method includes the voltage detection circuit receiving a detection voltage through a pin of the controller, and determining whether a discharge signal is generated based on the change of the detection voltage, wherein the detection voltage is generated by an input voltage input to the power converter, the input voltage being an AC input voltage or a DC input voltage, and the discharge signal lasting for a predetermined time; and the discharge circuit discharging the X-capacitor according to the discharge signal.

[0021] In one embodiment of the present invention, when the input voltage is the AC input voltage and the detection voltage does not change periodically in a first predetermined time, the voltage detection circuit generates the discharge signal after the first predetermined time, wherein the predetermined time is longer than the first predetermined time.

[0022] In one embodiment of the present invention, when the input voltage is the DC input voltage and the detection voltage is a certain value in a first predetermined time, the voltage detection circuit generates the discharge signal after the first predetermined time, wherein the predetermined time is greater than the first predetermined time.

Implementation Method

[0024] Please refer to Figure 1, which is a schematic diagram of a controller 100 with a variable X capacitor discharge mechanism disclosed in a first embodiment of the present invention. The controller 100 is applied to the primary side of a power converter 200 and includes a voltage detection circuit 102 and a discharge circuit 104. The coupling relationship between the voltage detection circuit 102 and the discharge circuit 104 can be seen in Figure 1 and will not be repeated here. In addition, as shown in Figure 1, since the power converter 200 is not a key technical feature of the present invention, the power converter 200 only shows a bridge rectifier 202, a capacitor 204, and a power conversion circuit 206. In addition, as shown in Figure 1, the present invention is not limited to the controller 100 only including the voltage detection circuit 102 and the discharge circuit 104. That is to say, the controller 100 may include other functional circuits (not shown in Figure 1).

[0025] As shown in Figure 1, a high-voltage pin 106 of the controller 100 is coupled to both ends of an X capacitor 300, and the X capacitor 300 is coupled to a bridge rectifier 202. The voltage detection circuit 102 can receive a detection voltage VHV through the high-voltage pin 106 and determine whether a discharge signal DS is generated based on the change of the detection voltage VHV. The detection voltage VHV is generated by an input voltage VIN input to the power converter 200, and the input voltage VIN is provided by a voltage source 400. Next, please refer to Figure 2. Figure 2 is a timing diagram illustrating the detection voltage VHV, a discharge current IHV, the discharge signal DS, an X capacitor discharge detection, a brown-out protection detection, a low-voltage protection, and an over-load protection detection related to the operation of the controller 100 when the input voltage VIN is an AC input voltage. The low-voltage protection and the over-load protection are related to the power converter 200. As shown in Figure 2, after the voltage source 400 provides the input voltage VIN to the power converter 200 for a period of time, between time T0 and time T1, since the detection voltage VHV is generated by the input voltage VIN through diodes 302 and 304, those skilled in the art should know that the voltage detection circuit 102 can continuously detect the periodic change of the detection voltage VHV. Between time T0 and time T1, the controller 100 activates a capacitor discharge detection, a brown-out protection detection, and an overload protection detection. The capacitor discharge detection, the brown-out protection detection, and the overload protection detection are related to other functional circuits of the controller 100. As shown in Figure 2, at time T1, voltage source 400 is removed, so the input voltage VIN is the residual voltage on capacitor X 300. This causes the detection voltage VHV detected by voltage detection circuit 102 between time T1 and time T2 (i.e., a first predetermined time) to not change periodically. Therefore, voltage detection circuit 102 determines that input voltage VIN is off. The first predetermined time depends on actual design requirements, for example (but not limited to) 50ms. During this first predetermined time, controller 100 continuously activates capacitor X discharge detection, low voltage protection detection, and overload protection detection. Then, after time T2, voltage detection circuit 102 generates a discharge signal DS to discharge circuit 104, and discharge circuit 104 discharges capacitor X 300 through discharge current IHV and high voltage pin 106. The discharge signal DS and discharge current IHV last for a predetermined time until time T3. This predetermined time also depends on actual design requirements, for example (but not limited to) 230ms, and this predetermined time is greater than the first predetermined time.Additionally, as shown in Figure 2, at time T2, other functional circuits within the controller 100 will also simultaneously disable the low-voltage protection detection and the overload protection detection. At the end of the predetermined time (i.e., at time T3), the other functional circuits within the controller 100 will re-enable the low-voltage protection detection and disable the X-capacitor discharge detection. At the end of the predetermined time, because the voltage source 400 is removed and the discharge circuit 104 discharges the X-capacitor 300 through the discharge current IHV and the high-voltage pin 106, the detection voltage VHV will be less than a first reference voltage BNOLEVEL, and the first reference voltage BNOLEVEL is related to the low-voltage protection detection. Furthermore, in one embodiment of the invention, when other functional circuits re-enable the low-voltage protection detection, the overload protection detection remains disabled. As shown in Figure 2, after time T3, at a second predetermined time (i.e., at time T4), the controller 100 will enable the low-voltage protection, where the second predetermined time depends on actual design requirements and is, for example (but not limited to), 70 ms. Next, as shown in Figure 2, after the controller 100 activates the low voltage protection, the controller 100 enters the protection mode and shuts down. The controller 100 can be shut down in a way that, for example, the power supply voltage VCC used for the operation of the controller 100 can be turned off or removed.

[0026] Next, please refer to Figure 3. Figure 3 is a timing diagram illustrating the detection voltage VHV, input voltage VIN, discharge current IHV, discharge signal DS, X capacitor discharge detection, low voltage protection detection, low voltage protection and over-load protection detection related to the operation of controller 100 when the input voltage VIN is a DC input voltage. The low voltage protection and over-load protection are related to power converter 200. As shown in Figure 3, after the voltage source 400 provides the input voltage VIN to the power converter 200 for a period of time, between time T0 and time T1, since the detection voltage VHV is generated by the input voltage VIN through diodes 302 and 304, if the voltage across diodes 302 and 304 is ignored, the detection voltage VHV can be substantially equivalent to the input voltage VIN (that is, the detection voltage VHV is a certain value). The controller 100 activates the X capacitor discharge detection, the low voltage protection detection, and the overload protection detection, and the X capacitor discharge detection, the low voltage protection detection, and the overload protection detection are related to other functional circuits of the controller 100. As shown in Figure 3, because the detection voltage VHV is a DC voltage, the detection voltage VHV detected by the voltage detection circuit 102 between time T1 and time T2 (that is, the first predetermined time) remains unchanged. This first predetermined time depends on actual design requirements and is, for example, (but is not limited to) 50ms. During this first predetermined time, the controller 100 continuously activates the X capacitor discharge detection, the low voltage protection detection, and the overload protection detection. Then, after time T2, the voltage detection circuit 102 generates a discharge signal DS to the discharge circuit 104, and the discharge circuit 104 discharges the X capacitor 300 through the discharge current IHV and the high-voltage pin 106. The discharge signal DS and the discharge current IHV continue for the predetermined time until time T3. This predetermined time depends on actual design requirements and is, for example, (but is not limited to) 230ms, and is longer than the first predetermined time. Additionally, as shown in Figure 3, at time T2, other functional circuits within the controller 100 will also simultaneously disable the low-voltage protection detection and the overload protection detection. At the end of the predetermined time (i.e., at time T3), the other functional circuits within the controller 100 will re-enable the low-voltage protection detection and disable the X-capacitor discharge detection. As shown in Figure 3, during the predetermined time (i.e., at time T4), because the voltage source 400 is removed, the detection voltage VHV will be less than the first reference voltage BNOLEVEL, and the first reference voltage BNOLEVEL is related to the low-voltage protection detection. As shown in Figure 3, after time T3, at a second predetermined time (i.e., at time T5), the controller 100 will enable the low-voltage protection, where the second predetermined time depends on actual design requirements and is, for example (but not limited to), 70ms.Next, as shown in Figure 3, after the controller 100 activates the low voltage protection, the controller 100 enters the protection mode and shuts down. The controller 100 can be shut down in a way that, for example, the power supply voltage VCC used for the operation of the controller 100 can be turned off or removed.

[0027] Next, please refer to Figure 4. Figure 4 is a timing diagram illustrating the detection voltage VHV, input voltage VIN, discharge current IHV, discharge signal DS, X capacitor discharge detection, low voltage protection detection, and overload protection detection related to the operation of controller 100 when the input voltage VIN is the DC input voltage. The low voltage protection and overload protection are related to power converter 200. As shown in Figure 4, before time T2, the detection voltage VHV, input voltage VIN, discharge current IHV, discharge signal DS, X capacitor discharge detection, low voltage protection detection, and overload protection detection are the same as in Figure 3, and will not be repeated here. Then, after time T2, voltage detection circuit 102 generates discharge signal DS to discharge circuit 104, and discharge circuit 104 can discharge X capacitor 300 through discharge current IHV and high voltage pin 106. The discharge signal DS and discharge current IHV continue for the predetermined time until time T3. Additionally, as shown in Figure 4, at time T2, other functional circuits within the controller 100 will also simultaneously disable the low-voltage protection detection and the overload protection detection. At the end of the predetermined time (i.e., at time T3), these other functional circuits will re-enable the low-voltage protection detection and disable the X-capacitor discharge detection. As shown in Figure 4, at the end of the predetermined time (i.e., at time T3), because the voltage source 400 has not been removed, the detection voltage VHV will not be less than the first reference voltage BNOLEVEL, causing the controller 100 not to activate the low-voltage protection after time T3. Furthermore, as shown in Figure 4, at a third predetermined time (i.e., at time T4), because the voltage source 400 has not been removed, the detection voltage VHV will also be greater than a second reference voltage DCINLEVEL, causing the controller 100 to re-enable the overload protection. This third predetermined time depends on actual design requirements and is, for example (but not limited to), 230ms.

[0028] Next, please refer to Figures 5, 6, and 7, which are timing diagrams of the detection voltage VHV, X capacitor discharge, and detection signal S1 related to the operation of the controller 100, based on Figure 1, according to a second embodiment of the present invention. As shown in Figure 5, at time T0, the voltage source 400 provides the input voltage VIN to the power converter 200 to power it on. Between time T0 and time T1, because the voltage detection circuit 102 generates M detection signals S1 according to the periodic change of the detection voltage VHV, the voltage detection circuit 102 determines at time T1 that the voltage source 400 is an AC voltage source, where M is a positive integer and depends on the actual design requirements. Additionally, when the detected voltage VHV reaches a peak value VPK and then falls below a detection reference voltage VTH, the voltage detection circuit 102 can generate a detection signal S1. In one embodiment of the invention, the detection reference voltage VTH can be N times the peak value VPK (where 1 > N > 0) or equal to the peak value VPK minus a fixed voltage. As shown in Figure 6, between time T1 and time T2 (i.e., a fourth predetermined time, which also depends on actual design requirements, for example, 50ms), the voltage detection circuit 102 does not generate a detection signal. Therefore, the voltage detection circuit 102 determines that the voltage source 400 has been removed and generates a discharge signal DS after the fourth predetermined time (i.e., after time T2). Then, the discharge circuit 104 can discharge the X capacitor 300 through the discharge current IHV and the high-voltage pin 106, causing the detected voltage VHV to gradually decrease after time T2.

[0029] As shown in Figure 7, between time T0 and time T1 (that is, a fifth predetermined time, which also depends on the actual design requirements, for example (but not limited to) 50ms), because the detection voltage VHV does not change periodically, the voltage detection circuit 102 will not generate any detection signal. Therefore, the voltage detection circuit 102 determines that the voltage source 400 is a DC voltage source at time T1 and will not generate a discharge signal DS. That is to say, when the voltage detection circuit 102 determines that the voltage source 400 is the DC voltage source at time T1, the voltage detection circuit 102 turns off the function of discharging the X capacitor 300.

[0030] Please refer to Figure 8, which is a schematic diagram of a controller 100 with a variable X capacitor discharge mechanism disclosed in a third embodiment of the present invention. The difference between Figure 8 and Figure 1 is that the high-voltage pin 106 of the controller 100 is coupled to the output terminal of the bridge rectifier 202. Furthermore, the coupling relationship between the voltage detection circuit 102, the discharge circuit 104, the bridge rectifier 202, the capacitor 204, the power conversion circuit 206, the X capacitor 300, and the voltage source 400 can be referred to Figure 8, and will not be repeated here. Next, please refer to Figure 9, which is a timing diagram illustrating the detection voltage VHV, X capacitor discharge detection, undervoltage protection detection, and overload protection detection related to the operation of the controller 100 when the input voltage VIN is the AC input voltage, based on Figure 8. As shown in Figure 9, after the voltage source 400 provides the input voltage VIN to the power converter 200 for a period of time, because the high-voltage pin 106 is coupled to the output of the bridge rectifier 202 and the capacitor 204 has a large capacitance value, the input voltage VIN can be considered a constant value at time T1. This constant value is greater than the first reference voltage and the second reference voltage. The first reference voltage is related to the low-voltage protection detection, and the second reference voltage is related to the overload protection detection. Therefore, if the detection voltage VHV detected by the voltage detection circuit 102 between time T1 and time T2 (that is, the first predetermined time) remains at this constant value, the controller 100 will turn off the X capacitor discharge detection and keep the low-voltage protection detection and the overload protection detection on. Of course, if the detection voltage VHV detected by the voltage detection circuit 102 between time T1 and time T2 (that is, the first predetermined time) remains at this constant value, the controller 100 can also operate according to Figure 4 after time T2.

[0031] Please refer to Figure 10. Figure 10 is a timing diagram illustrating the detection voltage VHV, X capacitor discharge detection, undervoltage protection detection, and overload protection detection related to the operation of controller 100 when the input voltage VIN is the DC input voltage, based on Figure 8. As shown in Figure 10, after the voltage source 400 provides the input voltage VIN to the power converter 200 for a period of time, because the input voltage VIN is the DC input voltage, the input voltage VIN is a constant value at time T1. This constant value is greater than the first reference voltage and the second reference voltage. The first reference voltage is related to the undervoltage protection detection, and the second reference voltage is related to the overload protection detection. Therefore, since the input voltage VIN is the constant value after time T1, the operation of Figure 10 after time T1 is the same as the operation of Figure 9 after time T1, and will not be described again here.

[0032] Additionally, please refer to Figures 1, 2, 3, 4, 8, 9, 10, 11A, and 11B, where Figures 11A and 11B are flowcharts of an operation method for a controller 100 with a variable X capacitor discharge mechanism disclosed in the fourth embodiment of the present invention. The operation method in Figures 11A and 11B is described using the power converter 200 and controller 100 in Figure 1, and the detailed steps are as follows:

[0033] Step 1100: Voltage source 400 provides input voltage VIN to power converter 200 to power on;

[0034] Step 1102: The voltage detection circuit 102 determines whether the input voltage VIN is an AC input voltage or a DC input voltage based on the detected voltage VHV; if the input voltage VIN is the AC input voltage, proceed to step 1104; if the input voltage VIN is the DC input voltage, proceed to step 1106.

[0035] Step 1104: Controller 100 turns off the discharge detection of capacitor X;

[0036] Step 1106: Does the voltage detection circuit 102 detect a periodic change in the detection voltage VHV? If yes, proceed to step 1108; if no, skip to step 1110.

[0037] Step 1108: Controller 100 activates the X capacitor discharge detection, the low voltage protection detection and the overload protection detection, and jumps back to step 1106;

[0038] Step 1110: The voltage detection circuit 102 generates a discharge signal DS to the discharge circuit 104, and the controller 100 turns off the low voltage protection detection and the overload protection detection;

[0039] Step 1112: The voltage detection circuit 102 stops generating the discharge signal DS, and then the controller 100 restarts the low voltage protection and turns off the X capacitor discharge detection;

[0040] Step 1114: Voltage detection circuit 102 detects whether the detection voltage VHV is less than the first reference voltage; if yes, proceed to step 1116; if no, skip to step 1118;

[0041] Step 1116: Controller 100 is turned off;

[0042] Step 1118: Voltage detection circuit 102 detects whether the detection voltage VHV is less than the second reference voltage; if yes, jump back to step 1116; if no, jump to step 1120;

[0043] Step 1120: Controller 100 re-enables the overload protection detection.

[0044] The execution order of steps 1100 (corresponding to time T0), 1102), 1106 (corresponding to time T1~T2), 1110 (corresponding to time T2~T3), 1112 (corresponding to time T3), 1114 (corresponding to time T3~T4), and 1116 (corresponding to time T4) can be referred to the relevant explanation in Figure 2. Steps 1110, 1102, 1106, 1110, 1112, and 111... 4. The execution order of step 1116 can be referred to the relevant explanation in Figure 3. The execution order of steps 1110, 1102, 1106, 1110, 1112, 1114, and 1118 can be referred to the relevant explanation in Figure 4. The execution order of steps 1110, 1102, and 1104 can be referred to the relevant explanation in Figure 9. The execution order of steps 1110, 1102, and 1104 can also be referred to the relevant explanation in Figure 10. They will not be repeated here.

[0045] Additionally, please refer to Figures 5, 6, 7, and 12, where Figure 12 is a flowchart of an operation method for a controller 100 with a variable X capacitor discharge mechanism disclosed in the fifth embodiment of the present invention. The operation method in Figure 12 is described using the power converter 200 and controller 100 shown in Figure 1, and the detailed steps are as follows:

[0046] Step 1200: Voltage source 400 provides input voltage VIN to power converter 200 for power-on;

[0047] Step 1202: Does the voltage detection circuit 102 detect a periodic change in the detection voltage VHV? If yes, proceed to step 1206; if no, proceed to step 1204.

[0048] Step 1204: Controller 100 disables the discharge detection of capacitor X;

[0049] Step 1206: The voltage detection circuit 102 generates M detection signals based on the periodic change of the detection voltage VHV. After a predetermined time, it determines whether no detection signal S1 is generated. If yes, proceed to step 1208; if no, proceed to step 1206 again.

[0050] Step 1208: The voltage detection circuit 102 generates a discharge signal DS, and then the discharge circuit 104 discharges the X capacitor 300.

[0051] The execution order of steps 1200, 1202, 1206, 1206… can be referred to the relevant explanation in Figure 5. The execution order of steps 1200, 1202, 1206, and 1208 can be referred to the relevant explanation in Figure 6. The execution order of steps 1200, 1202, and 1204 can be referred to the relevant explanation in Figure 7. They will not be repeated here.

[0052] In summary, compared with the prior art, the controller with a variable X capacitor discharge mechanism provided by the present invention is not only applicable to power supplies that need to be compatible with both AC and DC input voltages, but also prevents the controller from being damaged or overheated due to the continuous discharge of the X capacitor under DC input voltage because the discharge signal lasts for a limited time. The above description is only a preferred embodiment of the present invention, and all equivalent variations and modifications made within the scope of the claims of this invention should be considered within the scope of this invention. [Simplified Explanation of the Diagram]

[0023] Figure 1 is a schematic diagram of a controller with a variable X-capacitor discharge mechanism disclosed in the first embodiment of the present invention. Figure 2 is a timing diagram illustrating the detection voltage, discharge current, discharge signal, X-capacitor discharge detection, brown-out protection detection, and over-load protection detection related to controller operation when the input voltage is an AC input voltage. Figure 3 is a timing diagram illustrating the detection voltage, input voltage, discharge current, discharge signal, X-capacitor discharge detection, brown-out protection detection, and over-load protection detection related to controller operation when the input voltage is a DC input voltage. Figure 4 is a timing diagram illustrating the detection voltage, input voltage, discharge current, discharge signal, X-capacitor discharge detection, brown-out protection detection, and over-load protection detection related to controller 100 operation when the input voltage is the DC input voltage. Figures 5, 6, and 7 are timing diagrams of the detection voltage, X-capacitor discharge, and detection signal related to controller operation, based on Figure 1, disclosed in the second embodiment of the present invention. Figure 8 is a schematic diagram of a controller with a variable X-capacitor discharge mechanism disclosed in the third embodiment of the present invention. Figure 9 is a timing diagram illustrating the detection voltage, X-capacitor discharge detection, undervoltage protection detection, and overload protection detection related to controller operation when the input voltage is the AC input voltage, based on Figure 8. Figure 10 is a timing diagram illustrating the detection voltage, X-capacitor discharge detection, undervoltage protection detection, and overload protection detection related to controller operation when the input voltage is the DC input voltage, based on Figure 8. Figures 11A and 11B are flowcharts of an operation method of a controller with a variable X-capacitor discharge mechanism disclosed in the fourth embodiment of the present invention. Figure 12 is a flowchart of an operation method of a controller with a variable X-capacitor discharge mechanism disclosed in the fifth embodiment of the present invention.

Claims

1. A controller with a variable X-capacitor discharge mechanism, wherein the controller is applied to a power converter and the X-capacitor is coupled to the power converter, the controller comprising: a voltage detection circuit for receiving a detection voltage through a pin of the controller, and determining whether a discharge signal is generated based on a change in the detection voltage, wherein the detection voltage is generated by an input voltage input to the power converter, the input voltage being an AC input voltage or a DC input voltage, and the discharge signal lasting for a predetermined time; and a discharge circuit coupled to the voltage detection circuit and the pin for discharging the X-capacitor according to the discharge signal, wherein the pin is coupled to two terminals of the X-capacitor, and the X-capacitor is coupled to a bridge rectifier included in the power converter; When the input voltage is the AC input voltage and the detected voltage does not change periodically within a first predetermined time, the voltage detection circuit generates the discharge signal after the first predetermined time, and the discharge circuit discharges the X capacitor through a discharge current and the pin, wherein the predetermined time is longer than the first predetermined time, and during the first predetermined time, the controller activates an X capacitor discharge detection, a brown-out protection detection, and an overload protection detection.

2. The controller as claimed in claim 1, wherein during the predetermined time, the controller disables the low voltage protection detection and the overload protection detection; after the predetermined time ends, the controller re-enables the low voltage protection detection and disables the X capacitor discharge detection; and after the controller re-enables the low voltage protection detection, and at a second predetermined time when the detected voltage is less than a first reference voltage, the controller activates a low voltage protection, wherein the first reference voltage is related to the low voltage protection detection.

3. A controller with a variable X-capacitor discharge mechanism, wherein the controller is applied to a power converter and the X-capacitor is coupled to the power converter, the controller comprising: a voltage detection circuit for receiving a detection voltage through a pin of the controller, and determining whether a discharge signal is generated based on the change of the detection voltage, wherein the detection voltage is generated by an input voltage input to the power converter, the input voltage being an AC input voltage or a DC input voltage, and the discharge signal lasting for a predetermined time; and a discharge circuit coupled to the voltage detection circuit and the pin for discharging the X-capacitor according to the discharge signal, wherein the pin is coupled to two terminals of the X-capacitor, and the X-capacitor is coupled to a bridge rectifier included in the power converter; When the input voltage is the DC input voltage and the detected voltage is a certain value within a first predetermined time, the voltage detection circuit generates the discharge signal after the first predetermined time, and the discharge circuit discharges the X capacitor through a discharge current and the pin, wherein the predetermined time is greater than the first predetermined time, and within the first predetermined time, the controller activates an X capacitor discharge detection, a low voltage protection detection, and an overload protection detection.

4. The controller as claimed in claim 3, wherein during the predetermined time, the controller disables the low voltage protection detection and the overload protection detection; after the predetermined time ends, the controller re-enables the low voltage protection detection and disables the X capacitor discharge detection; and after the controller re-enables the low voltage protection detection, and at a second predetermined time when the detected voltage is less than a first reference voltage, the controller activates a low voltage protection, wherein the first reference voltage is related to the low voltage protection detection.

5. The controller as claimed in claim 3, wherein during the predetermined time, the controller disables the low voltage protection detection and the overload protection detection, and after the predetermined time, the controller re-enables the low voltage protection detection and disables the X capacitor discharge detection, wherein during the predetermined time, the detection voltage is greater than a first reference voltage.

6. The controller as claimed in claim 5, wherein after the predetermined time has elapsed for a third predetermined time, when the detected voltage is the set value and is greater than a second reference voltage, the controller reactivates the overload protection detection, wherein the second reference voltage is related to the overload protection detection.

7. A controller with a variable X-capacitor discharge mechanism, wherein the controller is applied to a power converter and the X-capacitor is coupled to the power converter, the controller comprising: a voltage detection circuit for receiving a detection voltage through a pin of the controller and determining whether to generate a discharge signal based on changes in the detection voltage, wherein the detection voltage is generated by an input voltage input to the power converter, the input voltage being an AC input voltage or a DC input voltage, and the discharge signal lasting for a predetermined time; and a discharge circuit coupled to the voltage detection circuit and the pin for discharging the X-capacitor according to the discharge signal, wherein the pin is coupled to two terminals of the X-capacitor, and the X-capacitor is coupled to a bridge rectifier included in the power converter; wherein the voltage detection circuit generates multiple detection signals according to periodic changes in the detection voltage, and if no detection signal is generated within a fourth predetermined time after the voltage detection circuit generates the multiple detection signals, the voltage detection circuit generates the discharge signal after the fourth predetermined time.

8. The controller as claimed in claim 7, wherein when the detected voltage reaches a peak value and then falls below a detection reference voltage, the voltage detection circuit generates a detection signal.

9. The controller as claimed in claim 7, wherein after a voltage source provides an input voltage to the power converter for a fifth predetermined time and the voltage detection circuit does not generate a detection signal during the fifth predetermined time, the voltage detection circuit does not generate the discharge signal after the fifth predetermined time.

10. A controller having a variable X-capacitor discharge mechanism, wherein the controller is applied to a power converter and the X-capacitor is coupled to the power converter, the controller comprising: a voltage detection circuit for receiving a detection voltage through a pin of the controller, and determining whether a discharge signal is generated based on a change in the detection voltage, wherein the detection voltage is generated by an input voltage input to the power converter, the input voltage being an AC input voltage or a DC input voltage, and the discharge signal lasting for a predetermined time; and a discharge circuit coupled to the voltage detection circuit and the pin for discharging the X-capacitor according to the discharge signal; wherein the pin is coupled to the output terminal of a bridge rectifier included in the power converter, and the X-capacitor is coupled to the bridge rectifier; When the input voltage is the AC input voltage and the detected voltage is a certain value for a first predetermined time, the controller turns off the X capacitor discharge detection and keeps on the low voltage protection detection and the overload protection detection. The set value is greater than a first reference voltage and a second reference voltage. The first reference voltage is related to the low voltage protection detection and the second reference voltage is related to the overload protection detection.

11. The controller of claim 10, wherein when the input voltage is the DC input voltage and the detected voltage is the set value at the first predetermined time, the controller disables the X capacitor discharge detection and keeps the low voltage protection detection and the overload protection detection continuously enabled, wherein the set value is greater than the first reference voltage and the second reference voltage, the first reference voltage being related to the low voltage protection detection and the second reference voltage being related to the overload protection detection.

12. A method of operating a controller with a variable X-capacitor discharge mechanism, wherein the controller is applied to a power converter, the X-capacitor is coupled to the power converter, and the controller includes a voltage detection circuit and a discharge circuit, the method comprising: the voltage detection circuit receiving a detection voltage through a pin of the controller, and determining whether a discharge signal is generated based on the change of the detection voltage, wherein the detection voltage is generated by an input voltage input to the power converter, the input voltage being an AC input voltage or a DC input voltage, and the discharge signal lasting for a predetermined time; and the discharge circuit discharging the X-capacitor according to the discharge signal, wherein when the input voltage is the AC input voltage and the detection voltage does not change periodically within a first predetermined time, the voltage detection circuit generates the discharge signal after the first predetermined time, wherein the predetermined time is greater than the first predetermined time, and during the first predetermined time, the controller activates an X-capacitor discharge detection, a brown-out protection detection, and an overload protection detection.

13. The operating method as described in claim 12, wherein when the input voltage is the DC input voltage and the detected voltage is a certain value during the first predetermined time, the voltage detection circuit generates the discharge signal after the first predetermined time, wherein the predetermined time is greater than the first predetermined time.

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