Power control circuit

Abstract

The invention discloses a power control circuit which comprises a power detection and judgment circuit and a power feedback circuit, the power detection and judgment circuit can obtain the output voltage of a power amplifier and judge whether the amplitude of the output voltage of the power amplifier is smaller than a preset voltage threshold value or not, if yes, a first level is output, and if not, a second level is output; therefore, the power feedback circuit outputs a power feedback signal to the power amplifier, and the output voltage of the power amplifier is adjusted to a preset voltage threshold. Therefore, the output voltage of the power amplifier is detected, and the output power of the power amplifier is fed back and controlled, so that the power amplifier is automatically controlled, the output power of the power amplifier is ensured to meet requirements, and the stability of the output performance of the power amplifier is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a power control circuit. Background Art

[0002] With the rapid development of modern communication technology, the performance requirements for power amplifiers are getting higher and higher. Especially in the fields of mobile communications, satellite communications, navigation positioning and cellular mobile communications, the power amplifier is a key component of signal transmission, and its output stability and efficiency directly affect the performance of the entire system and user experience. However, traditional power amplifiers often experience output power fluctuations or efficiency declines during long-term operation due to factors such as ambient temperature changes or device aging, and cannot meet the needs. Therefore, it is necessary to control the output power of the power amplifier to maintain the stability of its output performance. Summary of the invention

[0003] The purpose of the present invention is to provide a power control circuit, which detects the output voltage of a power amplifier and feedback controls the output power of the power amplifier to achieve automatic control of the power amplifier, ensure that the output power of the power amplifier meets the demand, and the stability of the output performance of the power amplifier.

[0004] In order to solve the above technical problems, the present invention provides a power control circuit, comprising:

[0005] A power detection and judgment circuit, the input end of which is connected to the output end of the power amplifier, and is used to output a first level when the amplitude of the output voltage of the power amplifier is less than a preset voltage threshold;

[0006] A power feedback circuit, whose input end is connected to the output end of the power detection and judgment circuit, and whose output end is connected to the control end of the power amplifier, is used to output a power feedback signal to the power amplifier when receiving the first level, so as to adjust the output voltage of the power amplifier to the preset voltage threshold.

[0007] Preferably, the power detection and judgment circuit includes:

[0008] a rectifier circuit, the input end of which is connected to the output end of the power amplifier, and the output end of which is connected to the input end of the power judgment circuit, for rectifying the sine wave voltage into a DC voltage when the output voltage of the power amplifier is a sine wave voltage, the DC voltage being positively correlated with the amplitude of the sine wave voltage, and outputting the DC voltage when the output voltage of the power amplifier is DC power, the DC voltage being positively correlated with the amplitude of the DC power;

[0009] The power judgment circuit has an output end connected to the input end of the power feedback circuit, and is used to output the first level when the DC voltage is less than the preset voltage threshold.

[0010] Preferably, the rectifier circuit comprises:

[0011] A rectifier switch tube, wherein the control end is connected to the output end of the power amplifier, the first end is connected to the power supply voltage, and the second end is connected to the input end of the power judgment circuit, and is used to be turned on in the positive half cycle of the sinusoidal wave voltage and when the sinusoidal wave voltage is greater than the conduction voltage of the rectifier switch tube, so as to rectify the sinusoidal wave voltage into pulsed direct current, and after being turned on, adjust its own first impedance based on the size of the sinusoidal wave voltage in the positive half cycle, the size of the pulsed direct current is negatively correlated with the first impedance, and the first impedance is negatively correlated with the size of the sinusoidal wave voltage in the positive half cycle; turn on when the direct current is greater than the conduction voltage of the rectifier switch tube, and after being turned on, adjust its own first impedance based on the size of the direct current, and output the direct current voltage based on the first impedance, the size of the direct current voltage is negatively correlated with the first impedance, and the first impedance is negatively correlated with the size of the direct current;

[0012] A first filter capacitor, a first end of which is connected to the second end of the rectifier switch tube and a second end of which is grounded, and is used for filtering the pulsed direct current to output the direct current voltage;

[0013] A pull-down resistor has a first end connected to the second end of the rectifier switch tube and a second end grounded.

[0014] Preferably, the rectifier circuit further includes:

[0015] A bias voltage compensation circuit, the output end of which is connected to the control end of the rectifier switch tube, and is used to provide a bias voltage for the rectifier switch tube, wherein the bias voltage is greater than the conduction voltage of the rectifier switch tube;

[0016] The rectifier switch tube is specifically used to receive the bias voltage at its own control end, and to be turned on during the positive half cycle of the sinusoidal wave voltage or when the power amplifier outputs the direct current, and to adjust its own first impedance based on the size of the sinusoidal wave voltage or the size of the direct current to rectify the sinusoidal wave voltage into the pulsed direct current or to output the direct current voltage based on the direct current.

[0017] Preferably, the bias voltage compensation circuit comprises:

[0018] A first bias resistor, a first end of which is connected to the control end of the rectifier switch tube;

[0019] A second filter capacitor, a first end of which is connected to the second end of the first bias resistor, and a second end of which is grounded;

[0020] A second bias resistor, a first end of which is connected to a preset high level;

[0021] A bias switch tube, a first end connected to the second end of the second bias resistor and the second end of the first bias resistor, a control end connected to the second end of the second bias resistor, and a second end grounded, for providing the bias voltage to the control end of the rectifier switch tube after being turned on.

[0022] Preferably, the power determination circuit comprises:

[0023] A reference generation circuit, configured to output the preset voltage threshold based on a preset instruction;

[0024] A first voltage comparator, having a first input terminal connected to the output terminal of the reference generating circuit and a second input terminal connected to the output terminal of the power amplifier, is used to output the first level when the DC voltage is less than the preset voltage threshold.

[0025] Preferably, the power detection and judgment circuit is further configured to output a second level when the amplitude of the output voltage of the power amplifier is not less than the preset voltage threshold, and the second level is different from the first level;

[0026] The power feedback circuit is further configured to output a power holding signal to the power amplifier when receiving the second level, so as to keep the power amplifier at a current output voltage.

[0027] Preferably, the power feedback circuit comprises:

[0028] A latch, whose input end is connected to the output end of the power detection and judgment circuit, and whose output end is connected to the first input end of the first logic circuit, and is used to latch and output the second level when receiving the second level;

[0029] a filter circuit, wherein the input end is connected to the output end of the power detection and judgment circuit, and the output end is connected to the first input end of the second voltage comparator, and is used for filtering the first level when receiving the first level and generating a first voltage after filtering, wherein the maximum value of the first voltage is less than the voltage reference value; and filtering the second level when receiving the second level and generating a second voltage after filtering, wherein the minimum value of the second voltage is greater than the voltage reference value;

[0030] The second voltage comparator, the second input terminal of which is connected to the voltage reference value, is used to output a third level that is the same as the first level when receiving the first voltage; and output a fourth level that is the same as the second level when receiving the second voltage;

[0031] a first logic judgment circuit, wherein the first input terminal is connected to the output terminal of the latch, the second input terminal is connected to the output terminal of the second voltage comparator, and the output terminal is connected to the first input terminal of the third logic judgment circuit, and is used to output a fifth level that is the same as the first level when the second level is not received and / or the third level is received, and to output a sixth level that is the same as the second level when the second level and the fourth level are received;

[0032] a second logic judgment circuit, wherein the first input terminal is connected to a preset level, the second input terminal is connected to the output terminal of the power detection judgment circuit, and is configured to output a seventh level which is the same as the first level when the first level is received; and output an eighth level which is the same as the second level when the second level is received;

[0033] The third logic judgment circuit has a second input end connected to the output end of the second logic judgment circuit, and an output end connected to the control end of the power amplifier, and is used to output the power hold signal to the power amplifier when receiving the sixth level and / or the eighth level; and output the power feedback signal to the power amplifier when receiving the fifth level and the seventh level.

[0034] Preferably, the filtering circuit comprises:

[0035] an inverter, whose input end is connected to the output end of the power detection and judgment circuit, and is used to invert the first level to the second level when the first level is received; and invert the second level to the first level when the second level is received;

[0036] a first filter switch tube, a control end of which is connected to the inverter, a first end of which is connected to a power supply voltage, and is used to be turned on when receiving the first level to charge the voltage of the first input end of the second voltage comparator to the second voltage, and to be turned off when receiving the second level;

[0037] A second filter switch tube, having a control end and a first end connected to the output end of the inverter, a second end grounded, and configured to be turned off when receiving the first level, and turned on when receiving the second level;

[0038] a third filter switch tube, having a control end connected to the output end of the inverter, a first end connected to the second end of the first filter switch tube, and a second end grounded, and configured to be turned off when receiving the first level, and turned on when receiving the second level, so as to discharge the voltage at the first input end of the second voltage comparator;

[0039] The third filter capacitor has a first end connected to the second end of the first filter switch tube and a second end grounded, and is used to charge when the first filter switch tube is turned on and discharge when the second filter switch tube and the third filter switch tube are turned on.

[0040] Preferably, the filtering circuit further includes:

[0041] A first resistor whose first end is connected to the output end of the inverter and whose second end is connected to the first end of the second filter switch tube;

[0042] A second resistor having a first end connected to the second end of the first filter switch tube and a second end connected to the first end of the third filter switch tube.

[0043] The present application provides a power control circuit, including a power detection and judgment circuit and a power feedback circuit, wherein the power detection and judgment circuit can obtain the output voltage of the power amplifier and judge whether the amplitude of the output voltage of the power amplifier is less than a preset voltage threshold. If it is less than, the first level is output, so that the power feedback circuit outputs a power feedback signal to the power amplifier to adjust the output voltage of the power amplifier to the preset voltage threshold. It can be seen that in the present application, the output voltage of the power amplifier is detected and the output power of the power amplifier is controlled by feedback to realize automatic control of the power amplifier, so as to ensure that the output power of the power amplifier meets the demand and the stability of the output performance of the power amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 A schematic diagram of the structure of a power control circuit provided by the present invention;

[0046] Figure 2 A structural schematic diagram of a rectifier circuit provided by the present invention;

[0047] Figure 3 A schematic diagram of the structure of a power judgment circuit provided by the present invention;

[0048] Figure 4 A schematic structural diagram of a power feedback circuit provided by the present invention. DETAILED DESCRIPTION

[0049] The core of the present invention is to provide a power control circuit, which detects the output voltage of the power amplifier and feedback controls the output power of the power amplifier to achieve automatic control of the power amplifier, ensure that the output power of the power amplifier meets the demand, and the stability of the output performance of the power amplifier.

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Please refer to Figure 1 , Figure 1 A schematic diagram of a power control circuit provided by the present invention, the circuit comprising:

[0052] A power detection and judgment circuit 1, whose input end is connected to the output end of the power amplifier, is used to output a first level when the amplitude of the output voltage of the power amplifier is less than a preset voltage threshold;

[0053] The power feedback circuit 2 has an input end connected to the output end of the power detection and judgment circuit 1 and an output end connected to the control end of the power amplifier, and is used to output a power feedback signal to the power amplifier when receiving a first level to adjust the output voltage of the power amplifier to a preset voltage threshold.

[0054] The power amplifier in the prior art can amplify the input power by a preset multiple and then output it. However, if affected by factors such as ambient temperature, the output power of the power amplifier may differ greatly from the expected output power and cannot meet the actual power demand.

[0055] In order to solve the above technical problems, in the present application, a power detection and judgment circuit 1 is set at the output end of the power amplifier, which can collect the output voltage of the power amplifier and judge whether the amplitude of the output voltage of the power amplifier is less than the preset voltage threshold. If it is not less than the preset voltage threshold, the output power of the power amplifier can meet the power demand and no adjustment is required; conversely, if the amplitude of the output voltage of the power amplifier is less than the preset voltage threshold, the output power of the power amplifier does not meet the demand. At this time, a first level can be output so that the power feedback circuit 2 outputs a power feedback signal to the power amplifier, so as to adjust the output voltage of the power amplifier to the preset voltage threshold through negative feedback regulation.

[0056] Among them, power amplification is usually achieved through an amplifier tube in a power amplifier. Therefore, the power feedback signal in the present application can be a voltage signal. Feedback control of the amplifier tube is achieved by feeding back the output voltage of the power amplifier to the control end of the amplifier tube.

[0057] It should be noted that the output voltage of the power amplifier may be adjusted multiple times until the output voltage reaches a preset voltage threshold.

[0058] In summary, in the present application, the output voltage of the power amplifier is detected and the output power of the power amplifier is controlled by feedback to achieve automatic control of the power amplifier, thereby ensuring that the output power of the power amplifier meets the demand and the stability of the output performance of the power amplifier.

[0059] Based on the above embodiments:

[0060] Please refer to Figure 2 , Figure 2 A structural schematic diagram of a rectifier circuit provided by the present invention.

[0061] As a preferred embodiment, the power detection and judgment circuit 1 includes:

[0062] A rectifier circuit, the input end of which is connected to the output end of the power amplifier, and the output end of which is connected to the input end of the power judgment circuit, for rectifying the sine wave voltage into a DC voltage when the output voltage of the power amplifier is a sine wave voltage, the DC voltage being positively correlated with the amplitude of the sine wave voltage, and outputting a DC voltage when the output voltage of the power amplifier is DC power, the DC voltage being positively correlated with the amplitude of the DC power;

[0063] The power judgment circuit has an output end connected to the input end of the power feedback circuit 2, and is used to output a first level when the DC voltage is less than a preset voltage threshold.

[0064] In this embodiment, considering that the output voltage of the power amplifier may be a sinusoidal wave voltage or a direct current, a rectifier circuit is also provided for accurate regulation. The rectifier circuit can rectify the sinusoidal wave voltage output by the power amplifier into a direct current voltage, and the direct current voltage output by the rectifier circuit is positively correlated with the amplitude of the sinusoidal wave voltage and the amplitude of the direct current, that is, the direct current voltage can reflect the magnitude of the sinusoidal wave voltage and the direct current.

[0065] If the voltage output by the power amplifier is a DC voltage, the preset voltage threshold can be set according to the average value or maximum value of the DC voltage; if the voltage output by the power amplifier is a sinusoidal wave voltage, the preset voltage threshold can be set according to the effective value or amplitude of the sinusoidal wave voltage. This application does not limit this.

[0066] As a preferred embodiment, the rectifier circuit includes:

[0067] The rectifier switch tube Q1 has a control end connected to the output end of the power amplifier, a first end connected to the power supply voltage, and a second end connected to the input end of the power judgment circuit, and is used to be turned on in the positive half cycle of the sinusoidal wave voltage and when the sinusoidal wave voltage is greater than the conduction voltage of the rectifier switch tube Q1, so as to rectify the sinusoidal wave voltage into pulsed direct current, and adjust its own first impedance based on the magnitude of the sinusoidal wave voltage in the positive half cycle after being turned on, the magnitude of the pulsed direct current is negatively correlated with the first impedance, and the first impedance is negatively correlated with the magnitude of the sinusoidal wave voltage in the positive half cycle; it is turned on when the direct current is greater than the conduction voltage of the rectifier switch tube Q1, and after being turned on, it adjusts its own first impedance based on the magnitude of the direct current, and outputs a direct current voltage based on the first impedance, the magnitude of the direct current voltage is negatively correlated with the first impedance, and the first impedance is negatively correlated with the magnitude of the direct current;

[0068] A first filter capacitor, a first end of which is connected to the second end of the rectifier switch tube Q1 and a second end of which is grounded, and is used for filtering the pulsed direct current to output a direct current voltage;

[0069] The pull-down resistor R3 has a first end connected to the second end of the rectifier switch tube Q1 and a second end grounded.

[0070] In this embodiment, the rectifier circuit specifically includes a rectifier switch tube Q1, a first filter capacitor C1 and a pull-down resistor R3. The output power of the power amplifier is transmitted to the control end of the rectifier switch tube Q1. The rectifier switch tube Q1 is turned on in the positive half cycle of the sine wave voltage and the sine wave voltage is greater than the conduction voltage of the rectifier switch tube Q1, and is turned off in the negative half cycle of the sine wave voltage. When the rectifier switch tube Q1 is turned on, the power supply voltage is transmitted to the second end of the rectifier switch tube Q1 through the rectifier switch tube Q1 and transmitted to the first filter capacitor as a pulsed direct current. The first filter capacitor C1 then filters the pulsed direct current into a direct current voltage to achieve rectification of the sine wave voltage. The rectifier switch tube Q1 is also turned on when the power amplifier outputs direct current and the direct current is greater than the conduction voltage of the rectifier switch tube Q1.

[0071] The first impedance of the rectifier switch tube Q1 changes with the voltage of the control end. Specifically, when the voltage of the control end is large, the first impedance of the rectifier switch tube Q1 is small, and the output pulse direct current or direct current voltage is larger. When the voltage of the control end is small, the first impedance of the rectifier switch tube Q1 is large, and the output pulse direct current or direct current voltage is smaller. Based on this, the rectifier switch tube Q1 can output a pulse direct current that is positively correlated with the magnitude of the sine wave voltage in the positive half cycle of the sine wave voltage, or output a direct current voltage that is positively correlated with the magnitude of the direct current when the power amplifier outputs direct current, so that the first filter capacitor filters the pulse direct current into a direct current voltage that is positively correlated with the amplitude or effective value of the sine wave voltage. It should be noted that the voltage output by the power amplifier and loaded to the control end of the rectifier switch tube Q1 adjusts the first impedance of the rectifier switch tube Q1 to adjust the voltage division of the power supply voltage by the rectifier switch tube Q1. The maximum output voltage of the rectifier switch tube Q1 is the power supply voltage.

[0072] In the negative half cycle of the sinusoidal voltage, or when the magnitude of the sinusoidal voltage is smaller than the on-voltage of the rectifier switch tube Q1 and the magnitude of the direct current is smaller than the on-voltage of the rectifier switch tube Q1, the rectifier switch tube Q1 is turned off. At this time, the voltage at the second end of the rectifier switch tube Q1 is pulled down by the pull-down resistor R3, thereby outputting a low level.

[0073] Among them, the rectifier switch tube Q1 can be but is not limited to NMOS, the gate of NMOS is the control end, the drain is the first end, and the source is the second end. NMOS is not only small in size, light in weight, low in power consumption, long in life, high in electron mobility, small in on-resistance, small in layout area, strong in power supply suppression capability, and strong in transient response capability, but can also be integrated into existing circuits, occupying a small circuit area.

[0074] As a preferred embodiment, the rectifier circuit further includes:

[0075] A bias voltage compensation circuit, the output end of which is connected to the control end of the rectifier switch tube Q1, and is used to provide a bias voltage for the rectifier switch tube Q1, wherein the bias voltage is greater than the conduction voltage of the rectifier switch tube Q1;

[0076] The rectifier switch tube Q1 is specifically used to receive a bias voltage at its own control end, and to be turned on in the positive half cycle of the sinusoidal wave voltage or when the power amplifier outputs direct current, and to adjust its own first impedance based on the size of the sinusoidal wave voltage or the size of the direct current to rectify the sinusoidal wave voltage into pulsed direct current or output a direct current voltage based on the direct current.

[0077] Considering that the rectifier switch tube Q1 will only be turned on when the output voltage of the power amplifier is greater than the conduction voltage of the rectifier switch tube Q1, this will cause the rectifier circuit to be unable to conduct and unable to rectify the sine wave voltage output by the power amplifier when the output voltage of the power amplifier is small, or some power is consumed in the rectifier circuit, resulting in the DC voltage output by the rectifier circuit being less than the output voltage of the power amplifier, thereby causing errors in subsequent judgment results. In this embodiment, a bias voltage compensation circuit is also provided, which can provide a bias voltage for the rectifier switch tube Q1, and the bias voltage is not less than the conduction voltage of the rectifier switch tube Q1, so as to ensure that the rectifier switch tube Q1 can be turned on regardless of the output voltage of the power amplifier, and the output power of the power amplifier is not lost.

[0078] After the bias voltage is added to the control end of the rectifier switch tube Q1, the first impedance of the rectifier switch tube Q1 can change with the magnitude of the output voltage of the power amplifier. For example, if the output voltage of the power amplifier is large, the first impedance of the rectifier switch tube Q1 is small, and the output pulse direct current is large. On the contrary, if the output voltage of the power amplifier is small, the first impedance of the rectifier switch tube Q1 is large, and the output pulse direct current is small. In addition, the pulse direct current output by the rectifier switch tube Q1 after the bias voltage is added is larger than the pulse direct current output by the rectifier switch tube Q1 when the bias voltage is not added. Correspondingly, the DC voltage output by the rectifier circuit is also larger after the bias voltage is added, thereby improving the accuracy of subsequent judgments.

[0079] For example, in the positive half cycle of the sinusoidal wave voltage, the voltage at the control end of the rectifier switch tube Q1 is the sum of the bias voltage and the sinusoidal wave voltage, and the rectifier switch tube Q1 can be turned on normally; in the negative half cycle of the sinusoidal wave voltage, the voltage at the control end of the rectifier switch tube Q1 is the difference between the bias voltage and the absolute value of the sinusoidal wave voltage. Therefore, the rectifier switch tube Q1 may be turned off, or the first impedance is large when it is turned on, depending on the selection of each component.

[0080] As a preferred embodiment, the bias voltage compensation circuit includes:

[0081] A first bias resistor R1, a first end of which is connected to the control end of the rectifier switch tube Q1;

[0082] A second filter capacitor C2, a first end of which is connected to the second end of the first bias resistor R1, and a second end of which is grounded;

[0083] A second bias resistor R2, a first end of which is connected to a preset high level;

[0084] The bias switch tube Q2 has a first end connected to the second end of the second bias resistor R2 and the second end of the first bias resistor R1, a control end connected to the second end of the second bias resistor R2, and a second end grounded, and is used to provide a bias voltage to the control end of the rectifier switch tube Q1 after being turned on.

[0085] The bias voltage compensation circuit in this embodiment specifically includes a first bias resistor R1, a second filter capacitor C2, a second bias resistor R2 and a bias switch tube Q2. The second bias resistor R2 can pull up the voltages at the first end and the control end of the bias switch tube Q2, thereby turning on the bias switch tube Q2, thereby adding the voltage at its first end to the second end of the first bias resistor R1, so that the first bias resistor R1 pulls up the voltage at the control end of the bias switch tube Q2 to the bias voltage.

[0086] Specifically, the bias voltage can be adjusted by adjusting the resistance of the second bias resistor R2 and the parameters of the bias switch tube Q2. When the bias voltage is large, the impedance of the rectifier switch tube Q1 is small. The output voltage of the power amplifier can also be amplified for judgment, thereby improving the accuracy of the judgment.

[0087] In addition, a second filter capacitor C2 is provided to filter out the clutter at the control end of the rectifier switch tube Q1 , thereby ensuring the matching degree between the DC voltage output by the rectifier switch tube Q1 and the sinusoidal voltage output by the power amplifier.

[0088] in, Figure 2 VPOWER is the output signal of the power amplifier, and VDC is the DC voltage output by the rectifier circuit. The bias switch Q2 can be but is not limited to NMOS, where the gate is the control terminal, the drain is the first terminal, and the source is the second terminal. Compared with a diode with forward conduction characteristics, NMOS is more flexible.

[0089] Please refer to Figure 3 , Figure 3 A schematic diagram of the structure of a power judgment circuit provided by the present invention.

[0090] As a preferred embodiment, the power determination circuit includes:

[0091] A reference generating circuit BGR, configured to output a preset voltage threshold based on a preset instruction;

[0092] The first voltage comparator COMP1 has a first input terminal connected to the output terminal of the reference generating circuit BGR, and a second input terminal connected to the output terminal of the power amplifier, and is used for outputting the first level when the DC voltage is less than a preset voltage threshold.

[0093] In this embodiment, the power judgment circuit includes a reference generation circuit BGR and a first voltage comparator COMP1, wherein the reference generation circuit BGR can output a preset voltage threshold according to a preset instruction, that is, the staff can issue a preset instruction to the reference generation circuit BGR according to the demand, and the preset instruction is related to the preset voltage threshold output by the desired power amplifier, and the reference generation circuit BGR can be implemented by an adjustable voltage, and the reference generation circuit BGR can output different voltages. The staff can select the switch corresponding to the voltage output by the reference generation circuit BGR according to actual needs. After turning on the switch, the reference generation circuit BGR can output the corresponding voltage, that is, the preset voltage threshold. Based on this, the staff can directly select the output voltage of the reference generation circuit BGR through the 3-8 decoder. The reference generation circuit BGR can output a reference voltage of 0.6V-2V, such as 0.6V, 0.8V, 1V, 1.2V, 1.4V, 1.6V, 1.8V and 2V, which is easy to operate. Of course, this application is not limited to this.

[0094] The selected preset voltage threshold may be determined based on the output voltage of the power amplifier and the parameters of the rectifier circuit.

[0095] The reference generating circuit BGR can output a preset voltage threshold to the first voltage comparator COMP1, and the second input terminal of the first voltage comparator COMP1 is connected to the output terminal of the power amplifier, or to the output terminal of the rectifier circuit. If the amplitude of the output voltage of the power amplifier is less than the preset voltage threshold, the power amplifier needs to be adjusted to output the first level.

[0096] The output end of the first voltage comparator COMP1 can be provided with two stages of inverters according to actual requirements to improve the driving capability of the first level.

[0097] in, Figure 3 VCOMP is the output signal of the first voltage comparator COMP1, which is the first level or the second level. VN is the preset voltage threshold output by the reference generating circuit BGR. When the DC voltage output by the rectifier circuit is not less than the preset voltage threshold, VCOMP is the second level. When the DC voltage output by the rectifier circuit is less than the preset voltage threshold, VCOMP is the first level.

[0098] As a preferred embodiment, the power detection and judgment circuit is further used to output a second level when the amplitude of the output voltage of the power amplifier is not less than a preset voltage threshold, and the second level is different from the first level;

[0099] The power feedback circuit 2 is further configured to output a power maintaining signal to the power amplifier when receiving the second level, so as to maintain the power amplifier at a current output voltage.

[0100] In this embodiment, if the output voltage of the power amplifier is not less than the preset voltage threshold, there is no need to adjust the power amplifier, and the output terminal of the first voltage comparator COMP1 can remain suspended, or output a second level different from the first level, which is not limited in this application. The second level can be a high level and the first level can be a low level.

[0101] In addition, whether the output of the power amplifier meets the requirements can be determined based on whether the level output by the first voltage comparator COMP1 is the first level or the second level, that is, a prompt module can be set to perform different prompts based on the first level and the second level.

[0102] Please refer to Figure 4 , Figure 4 A schematic structural diagram of a power feedback circuit provided by the present invention.

[0103] As a preferred embodiment, the power feedback circuit 2 includes:

[0104] A latch Q, whose input end is connected to the output end of the power detection and judgment circuit 1, and whose output end is connected to the first input end of the first logic circuit, is used to latch and output the second level when receiving the second level;

[0105] A filter circuit, wherein the input end is connected to the output end of the power detection and judgment circuit 1, and the output end is connected to the first input end of the second voltage comparator COMP2, and is used for filtering the first level when receiving the first level, and generating a first voltage after filtering, wherein the maximum value of the first voltage is less than the voltage reference value; and filtering the second level when receiving the second level, and generating a second voltage after filtering, wherein the minimum value of the second voltage is greater than the voltage reference value;

[0106] The second voltage comparator COMP2 has a second input terminal connected to a voltage reference value, and is used to output a third level that is the same as the first level when receiving the first voltage; and output a fourth level that is the same as the second level when receiving the second voltage;

[0107] A first logic judgment circuit U1, a first input terminal connected to the output terminal of the latch Q, a second input terminal connected to the output terminal of the second voltage comparator COMP2, an output terminal connected to the first input terminal of the third logic judgment circuit U3, for outputting a fifth level that is the same as the first level when the second level is not received and / or the third level is received, and outputting a sixth level that is the same as the second level when the second level and the fourth level are received;

[0108] The second logic judgment circuit U2 has a first input terminal connected to the preset level LD, and a second input terminal connected to the output terminal of the power detection judgment circuit 1, and is used to output a seventh level that is the same as the first level when receiving the first level; and output an eighth level that is the same as the second level when receiving the second level;

[0109] The third logic judgment circuit U3 has a second input terminal connected to the output terminal of the second logic judgment circuit U2, and an output terminal connected to the control terminal of the power amplifier, and is used to output a power hold signal to the power amplifier when the sixth level and / or the eighth level are received; and output a power feedback signal to the power amplifier when the fifth level and the seventh level are received.

[0110] In this embodiment, the power feedback circuit 2 includes a latch Q, a filter circuit, a second voltage comparator COMP2, a first logic judgment circuit U1, a second logic judgment circuit U2 and a third logic judgment circuit U3, wherein, when the level output by the power detection judgment circuit 1 is the second level, the latch Q can latch the second level and maintain the output of the second level, and the filter circuit can filter the second level and output a second voltage, the second voltage is greater than the voltage reference value of the second voltage comparator COMP2, and at this time, the second voltage comparator COMP2 outputs a fourth level that is the same as the second level; and when the level output by the power detection judgment circuit 1 is the first level, if the latch Q has latched and output the second level, the latch Q can maintain the output of the second level, and if the latch Q has not latched the second level, the latch Q can output the first level, or the output end is suspended, and the filter circuit can also filter the first level, and output a first voltage whose maximum value is less than the voltage reference value to the second voltage comparator COMP2, and at this time, the second voltage comparator COMP2 outputs a third level that is the same as the first level. The second logic judgment circuit U2 can maintain the output of the eighth level when the power amplifier outputs direct current and the power detection judgment circuit 1 outputs a stable direct current voltage, so that when the second logic judgment circuit U2 outputs the eighth level, the third logic judgment circuit U3 outputs a power holding signal to the power amplifier regardless of the output of the first logic judgment circuit U1, that is, as long as the direct current output of the power amplifier meets the preset voltage threshold, the power holding signal can be directly output; and if the power amplifier outputs a sinusoidal voltage that meets the preset voltage threshold, the output of the power amplifier may be a pulse voltage, and the power amplifier outputs the first level and the second level alternately. At this time, the latch Q is required to latch the second level immediately upon receiving the second level. During the charging and discharging process, the third filter capacitor C3 in the filter circuit can keep the voltage at the first input terminal of the second voltage comparator COMP2 above the voltage reference value, so that the second voltage comparator COMP2 outputs the fourth level. The first logic judgment circuit U1 can output the sixth level after receiving the second level and the fourth level at the same time. The third logic judgment circuit U3 outputs a power retention signal after receiving the sixth level and the eighth level. In addition, the third logic judgment circuit U3 can output a power retention signal after receiving any one of the sixth level and the eighth level. However, if the third logic judgment circuit U3 does not receive any one of the sixth level and the eighth level, but only receives the fifth level and the seventh level, it outputs a power feedback signal.

[0111] It should be noted that the voltage reference value VREF can be set according to actual needs, such as being set to 0.4V, and this application does not limit this.

[0112] By latching the second level by latch Q, it can be ensured that no matter the power amplifier outputs direct current or sinusoidal voltage, a stable level output can be maintained. In particular, when the output is a sinusoidal voltage, since the sinusoidal voltage is high level for half a cycle and low level for half a cycle, the DC voltage rectified by the rectifier circuit also has a difference between high and low levels. By latching by latch Q, a high level can be maintained during the entire sinusoidal voltage output process. Among them, the first level is a low level and the second level is a high level. Of course, the specific situation of the first level and the second level can be determined according to the actual circuit connection method. It should also be noted that the first logic judgment circuit U1 can be, but is not limited to, an AND gate.

[0113] The second logic judgment circuit U2 may be but is not limited to an AND gate, and the third logic judgment circuit U3 may be but is not limited to an OR gate, which have simple structures, low costs, and are easy to control.

[0114] The output end of the third logic judgment circuit U3 can be provided with a two-stage inverter Q3 according to actual requirements to improve the driving capability of the power feedback signal or the power holding signal VOUT.

[0115] Specifically, if the first level is a low level and the second level is a high level, when the power detection judgment circuit 1 continuously outputs a low level, the voltage at the first input terminal of the second voltage comparator COMP2 always maintains the first voltage and outputs a low level, the latch Q outputs a low level or is suspended, the first logic judgment circuit U1 outputs a low level, the second logic judgment circuit U2 outputs a low level, and the third logic judgment circuit U3 outputs a power feedback signal; when the power detection judgment circuit 1 continuously outputs a high level, the voltage at the first input terminal of the second voltage comparator COMP2 always maintains the second voltage and outputs a high level, the latch Q maintains The first logic judgment circuit U1 outputs a high level, the second logic judgment circuit U2 outputs a high level, and the third logic judgment circuit U3 outputs a power holding signal; when the power detection judgment circuit 1 outputs a pulse voltage with alternating high and low levels, the voltage at the first input terminal of the second voltage comparator COMP2 always remains greater than the voltage reference value and outputs a high level. The latch Q continues to output a high level after receiving a high level for the first time. The first logic judgment circuit U1 outputs a pulse voltage with alternating high and low levels, the second logic judgment circuit U2 outputs a high level, and the third logic judgment circuit U3 outputs a power holding signal. Based on this, the present application can be compatible with the automatic power control and adjustment of power amplifiers with AC output and DC output.

[0116] As a preferred embodiment, the filter circuit includes:

[0117] The inverter Q3, whose input end is connected to the output end of the power detection and judgment circuit 1, is used to invert the first level to the second level when receiving the first level; and invert the second level to the first level when receiving the second level;

[0118] A first filter switch tube Q4, a control end of which is connected to the inverter Q3, a first end of which is connected to the power supply voltage, and is used to be turned on when receiving a first level to charge the voltage of the first input end of the second voltage comparator COMP2 to a second voltage, and to be turned off when receiving the second level;

[0119] A second filter switch tube Q5, having a control end and a first end connected to the output end of the inverter Q3, and a second end grounded, for turning off when receiving a first level, and turning on when receiving a second level;

[0120] a third filter switch tube Q6, having a control end connected to the output end of the inverter Q3, a first end connected to the second end of the first filter switch tube Q4, and a second end grounded, and configured to be turned off when receiving a first level, and turned on when receiving a second level, so as to discharge the voltage at the first input end of the second voltage comparator COMP2;

[0121] The third filter capacitor C3 has a first end connected to the second end of the first filter switch tube Q4 and a second end grounded, and is used for charging when the first filter switch tube Q4 is turned on, and discharging when the second filter switch tube Q5 and the third filter switch tube Q6 are turned on.

[0122] In this embodiment, the inverter Q3 in the filter circuit can invert the first level or the second level output by the power detection and judgment circuit 1. If the power detection and judgment circuit 1 outputs the second level, the inverter Q3 inverts the second level to the first level, thereby turning on the first filter switch tube Q4, and turning off the second filter switch tube Q5 and the third filter switch tube Q6. The first filter switch tube Q4 charges the voltage of the first input terminal of the second voltage comparator COMP2 to the second voltage, that is, the third filter capacitor C3 is charged to the second voltage. In the process of turning on the first filter switch tube Q4, the first input terminal of the second voltage comparator COMP2 The voltage of the first input terminal of the second voltage comparator COMP2 is always the second voltage; if the power detection judgment circuit 1 outputs the first level, the inverter Q3 inverts the first level to the second level, and the first filter switch tube Q4 is turned off, the second filter switch tube Q5 and the third filter switch tube Q6 are turned on, and the third filter switch tube Q6 discharges the voltage of the first input terminal of the second voltage comparator COMP2. If the power judgment circuit continues to output the first level, that is, the output voltage of the power amplifier continues to fail to meet the preset voltage threshold, the voltage of the first input terminal of the second voltage comparator COMP2 is discharged to the first voltage, that is, the third filter capacitor C3 is discharged to the first voltage, and the voltage of the first input terminal of the second voltage comparator COMP2 is discharged to the first voltage. During the process of the wave switch tube Q4 being turned off, the voltage at the first input terminal of the second voltage comparator COMP2 is always the first voltage. If the power detection and judgment circuit 1 outputs the first level for a short time, that is, the DC voltage output by the power detection and judgment circuit 1 is a clock signal, the voltage at the first input terminal of the second voltage comparator COMP2, that is, the voltage of the third filter capacitor C3 has not been discharged to be less than the voltage reference value, the power detection and judgment circuit 1 re-outputs the second level, and the first filter switch tube Q4 is turned on again, and the voltage at the first input terminal of the second voltage comparator COMP2, that is, the voltage of the third filter capacitor C3 is charged to the second voltage reference value. voltage; if the power detection and judgment circuit 1 outputs the first level for a long time, that is, the DC voltage output by the power detection and judgment circuit 1 is the first level for a long time and the second level for a short time, the voltage at the first input terminal of the second voltage comparator COMP2, that is, the voltage of the third filter capacitor C3 is discharged to be less than the voltage reference value during the process of the power detection and judgment circuit 1 outputting the first level. After a period of time, the power detection and judgment circuit 1 re-outputs the second level, and the first filter switch tube Q4 is turned on again, and the voltage at the first input terminal of the second voltage comparator COMP2, that is, the voltage of the third filter capacitor C3 is charged to the second voltage again.

[0123] As a preferred embodiment, the filter circuit further includes:

[0124] A first resistor R11 having a first end connected to the output end of the inverter Q3 and a second end connected to the first end of the second filter switch tube Q5;

[0125] A second resistor R12 having a first end connected to the second end of the first filter switch tube Q4 and a second end connected to the first end of the third filter switch tube Q6.

[0126] In addition, a first resistor R11 is provided between the first end of the second filter switch tube Q5 and the output end of the inverter Q3, and a second resistor R12 is provided between the first end of the third filter switch tube Q6 and the first input end of the second voltage comparator COMP2, which can filter or pull down the voltage.

[0127] It should be noted that the first filter switch tube Q4 can be but is not limited to a PMOS, the gate of the PMOS is the control end, the source is the first end, the drain is the second end, and it is turned on when the first level received by the gate is a low level, and it is turned off when the second level is a high level; the second filter switch tube Q5 and the third filter switch tube Q6 can be but are not limited to NMOS, the gate of the NMOS is the control end, the drain is the first end, the source is the second end, and it is turned off when the first level received by the gate is a low level, and it is turned on when the second level is a high level.

[0128] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0129] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power control circuit, characterized in that: include: A power detection and judgment circuit, the input end of which is connected to the output end of the power amplifier, and is used to output a first level when the amplitude of the output voltage of the power amplifier is less than a preset voltage threshold; A power feedback circuit, whose input end is connected to the output end of the power detection and judgment circuit, and whose output end is connected to the control end of the power amplifier, is used to output a power feedback signal to the power amplifier when receiving the first level, so as to adjust the output voltage of the power amplifier to the preset voltage threshold.

2. The power control circuit according to claim 1, characterized in that: The power detection and judgment circuit comprises: a rectifier circuit, the input end of which is connected to the output end of the power amplifier, and the output end of which is connected to the input end of the power judgment circuit, for rectifying the sine wave voltage into a DC voltage when the output voltage of the power amplifier is a sine wave voltage, the DC voltage being positively correlated with the amplitude of the sine wave voltage, and outputting the DC voltage when the output voltage of the power amplifier is DC power, the DC voltage being positively correlated with the amplitude of the DC power; The power judgment circuit has an output end connected to the input end of the power feedback circuit, and is used to output the first level when the DC voltage is less than the preset voltage threshold.

3. The power control circuit according to claim 2, characterized in that: The rectifier circuit comprises: A rectifier switch tube, wherein the control end is connected to the output end of the power amplifier, the first end is connected to the power supply voltage, and the second end is connected to the input end of the power judgment circuit, and is used to be turned on in the positive half cycle of the sinusoidal wave voltage and when the sinusoidal wave voltage is greater than the conduction voltage of the rectifier switch tube, so as to rectify the sinusoidal wave voltage into pulsed direct current, and after being turned on, adjust its own first impedance based on the size of the sinusoidal wave voltage in the positive half cycle, the size of the pulsed direct current is negatively correlated with the first impedance, and the first impedance is negatively correlated with the size of the sinusoidal wave voltage in the positive half cycle; turn on when the direct current is greater than the conduction voltage of the rectifier switch tube, and after being turned on, adjust its own first impedance based on the size of the direct current, and output the direct current voltage based on the first impedance, the size of the direct current voltage is negatively correlated with the first impedance, and the first impedance is negatively correlated with the size of the direct current; A first filter capacitor, a first end of which is connected to the second end of the rectifier switch tube and a second end of which is grounded, and is used for filtering the pulsed direct current to output the direct current voltage; A pull-down resistor has a first end connected to the second end of the rectifier switch tube and a second end grounded.

4. The power control circuit according to claim 3, characterized in that: The rectifier circuit also includes: A bias voltage compensation circuit, the output end of which is connected to the control end of the rectifier switch tube, and is used to provide a bias voltage for the rectifier switch tube, wherein the bias voltage is greater than the conduction voltage of the rectifier switch tube; The rectifier switch tube is specifically used to receive the bias voltage at its own control end, and to be turned on during the positive half cycle of the sinusoidal wave voltage or when the power amplifier outputs the direct current, and to adjust its own first impedance based on the size of the sinusoidal wave voltage or the size of the direct current to rectify the sinusoidal wave voltage into the pulsed direct current or to output the direct current voltage based on the direct current.

5. The power control circuit according to claim 4, characterized in that: The bias voltage compensation circuit comprises: A first bias resistor, a first end of which is connected to the control end of the rectifier switch tube; A second filter capacitor, a first end of which is connected to the second end of the first bias resistor, and a second end of which is grounded; A second bias resistor, a first end of which is connected to a preset high level; A bias switch tube, a first end connected to the second end of the second bias resistor and the second end of the first bias resistor, a control end connected to the second end of the second bias resistor, and a second end grounded, for providing the bias voltage to the control end of the rectifier switch tube after being turned on.

6. The power control circuit according to claim 2, characterized in that: The power judgment circuit comprises: A reference generation circuit, configured to output the preset voltage threshold based on a preset instruction; A first voltage comparator, having a first input terminal connected to the output terminal of the reference generating circuit and a second input terminal connected to the output terminal of the power amplifier, is used for outputting the first level when the DC voltage is less than the preset voltage threshold.

7. The power control circuit according to any one of claims 1 to 6, characterized in that: The power detection and judgment circuit is further configured to output a second level when the amplitude of the output voltage of the power amplifier is not less than the preset voltage threshold, and the second level is different from the first level; The power feedback circuit is further configured to output a power holding signal to the power amplifier when receiving the second level, so as to keep the power amplifier at a current output voltage.

8. The power control circuit according to claim 7, characterized in that: The power feedback circuit comprises: A latch, whose input end is connected to the output end of the power detection and judgment circuit, and whose output end is connected to the first input end of the first logic circuit, and is used to latch and output the second level when receiving the second level; a filter circuit, wherein the input end is connected to the output end of the power detection and judgment circuit, and the output end is connected to the first input end of the second voltage comparator, and is used for filtering the first level when receiving the first level and generating a first voltage after filtering, wherein the maximum value of the first voltage is less than the voltage reference value; and filtering the second level when receiving the second level and generating a second voltage after filtering, wherein the minimum value of the second voltage is greater than the voltage reference value; The second voltage comparator, the second input terminal of which is connected to the voltage reference value, is used to output a third level that is the same as the first level when receiving the first voltage; and output a fourth level that is the same as the second level when receiving the second voltage; a first logic judgment circuit, wherein the first input terminal is connected to the output terminal of the latch, the second input terminal is connected to the output terminal of the second voltage comparator, and the output terminal is connected to the first input terminal of the third logic judgment circuit, and is used to output a fifth level that is the same as the first level when the second level is not received and / or the third level is received, and to output a sixth level that is the same as the second level when the second level and the fourth level are received; a second logic judgment circuit, wherein the first input terminal is connected to a preset level, the second input terminal is connected to the output terminal of the power detection judgment circuit, and is configured to output a seventh level which is the same as the first level when the first level is received; and output an eighth level which is the same as the second level when the second level is received; The third logic judgment circuit has a second input end connected to the output end of the second logic judgment circuit, and an output end connected to the control end of the power amplifier, and is used to output the power hold signal to the power amplifier when receiving the sixth level and / or the eighth level; and output the power feedback signal to the power amplifier when receiving the fifth level and the seventh level.

9. The power control circuit according to claim 8, characterized in that: The filtering circuit comprises: an inverter, whose input end is connected to the output end of the power detection and judgment circuit, and is used to invert the first level to the second level when the first level is received; and invert the second level to the first level when the second level is received; a first filter switch tube, a control end of which is connected to the inverter, a first end of which is connected to a power supply voltage, and is used to be turned on when receiving the first level to charge the voltage of the first input end of the second voltage comparator to the second voltage, and to be turned off when receiving the second level; A second filter switch tube, having a control end and a first end connected to the output end of the inverter, a second end grounded, and configured to be turned off when receiving the first level, and turned on when receiving the second level; a third filter switch tube, having a control end connected to the output end of the inverter, a first end connected to the second end of the first filter switch tube, and a second end grounded, and configured to be turned off when receiving the first level, and turned on when receiving the second level, so as to discharge the voltage at the first input end of the second voltage comparator; The third filter capacitor has a first end connected to the second end of the first filter switch tube and a second end grounded, and is used to charge when the first filter switch tube is turned on and discharge when the second filter switch tube and the third filter switch tube are turned on.

10. The power control circuit according to claim 9, characterized in that: The filter circuit also includes: A first resistor whose first end is connected to the output end of the inverter and whose second end is connected to the first end of the second filter switch tube; A second resistor having a first end connected to the second end of the first filter switch tube and a second end connected to the first end of the third filter switch tube.

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