Automatic power control radio frequency power amplifier circuit based on current detection
By employing current sensing technology in the RF power amplifier and utilizing operational amplifiers and capacitors to achieve feedback control, the problems of high size and cost of RF couplers are solved, and low-cost, high-stability automatic power control is realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2026-04-07
AI Technical Summary
Existing automatic power control technology for RF power amplifiers suffers from problems such as high size and cost of RF couplers and output power loss introduced by the coupling circuit in small wireless communication devices.
The operating current of the RF power amplifier is detected using common, low-cost components such as operational amplifiers, resistors, and capacitors. The detected current is then converted into a feedback control voltage to achieve automatic power control.
It reduces circuit costs, is suitable for small wireless communication devices with high space requirements, ensures stable output power, and improves system reliability and stability.
Smart Images
Figure CN224097692U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to electronic circuit field especially relates to a kind of automatic power control radio frequency power amplifier circuit based on current detection. BACKGROUND
[0002] The automatic power control technology of radio frequency power amplifier is a kind of technology for adjusting and keeping the stable technology of power amplifier output power.This technology is especially important in wireless communication system, because the power level of signal has direct influence on communication quality, coverage and the spectrum efficiency of system.Usually the automatic power control of radio frequency power amplifier adopts radio frequency coupling detection in the radio frequency output end of radio frequency power amplifier, then radio frequency coupling signal is detected and converted into feedback control voltage to realize.This method has the shortcomings such as the size and price of radio frequency coupler are higher, output power loss is introduced by coupling circuit, etc., and it is not applicable in small size handheld wireless communication equipment such as intercom. CONTENT OF UTILITY MODEL
[0003] In view of the problems existing in the prior art, the utility model provides an automatic power control radio frequency power amplifier circuit based on current detection. Mainly using operational amplifier, resistance, capacitor and other general low-cost devices to realize the detection of radio frequency power amplifier working current, and convert the detection current into feedback control voltage, realize the automatic power control of radio frequency power amplifier, to solve the problems existing in the prior art.
[0004] The utility model discloses taken technical scheme is: a kind of automatic power control radio frequency power amplifier circuit based on current detection, comprising: operational amplifier power input, radio frequency power amplifier power input, radio frequency input, radio frequency output, power control voltage input, operational amplifier, radio frequency power amplifier, coupling capacitor, matching inductance, current detection resistance, gain resistance, bias resistance, filter resistance, bypass capacitor and choke inductance;The operational amplifier power input is used to provide power supply for operational amplifier, the radio frequency power amplifier power input is used to provide power supply for radio frequency power amplifier, the radio frequency input is used to input radio frequency signal, the radio frequency output is used to output amplified radio frequency signal, the power control voltage input is used to control radio frequency power amplifier power level, the operational amplifier is used to receive error voltage and power control voltage and generate feedback bias voltage by difference amplification, adjust the power output of radio frequency power amplifier, and the radio frequency power amplifier is used to amplify radio frequency signal processing;Specific circuit includes radio frequency input RFI, radio frequency output RFO, operational amplifier power input VCC1, radio frequency power amplifier power input VCC2, power control voltage input VP, resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, resistance R8, resistance R9, resistance R10, resistance R11, capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, capacitor C6, inductance L1, inductance L2, inductance L3, radio frequency power amplifier VT1, operational amplifier N1A and N1B constitute double operational amplifier chip N1;Specific circuit connection is as follows: radio frequency input RFI is connected with one end of capacitor C1, the other end of capacitor C1 is connected with one end of inductance L1, the other end of inductance L1 is connected with one end of resistance R1 and gate of radio frequency power amplifier VT1 respectively;The other end of resistance R1 is connected with one end of capacitor C2 and one end of resistance R2 respectively, the other end of capacitor C2 is grounded, the other end of resistance R2 is connected with output of operational amplifier N1B and one end of resistance R3 respectively, positive power supply end of operational amplifier N1B is connected with operational amplifier power input VCC1 and one end of capacitor C6 respectively, the other end of capacitor C6 is grounded;The same direction input of operational amplifier N1B is connected with power control voltage input VP through resistance R4;The other end of resistance R3 is connected with reverse input of operational amplifier N1B and one end of resistance R5 respectively, the other end of resistance R5 is connected with output of operational amplifier N1A and one end of resistance R6 respectively, the other end of resistance R6 is connected with reverse input of operational amplifier N1A, resistance R8 and one end of resistance R10 respectively, the other end of resistance R8 is grounded, negative power supply end of operational amplifier N1A is grounded, the same direction input of operational amplifier N1A is connected with one end of resistance R7 and one end of resistance R9 respectively, the other end of resistance R7 is grounded.The other end of the resistor R9 is connected with one end of the resistor R11, one end of the capacitor C3 and the radio frequency power amplifier power input terminal VCC2 respectively, the other end of the resistor R11 is connected with the other end of the resistor R10, one end of the inductor L2 and one end of the capacitor C4 respectively, the other end of the inductor L2 is connected with the drain of the radio frequency power amplifier VT1 and one end of the capacitor C5 respectively, the other end of the capacitor C5 is connected with the inductor L3, the other end of the inductor L3 is connected with the radio frequency output terminal RFO, and the other end of the capacitor C3, the other end of the capacitor C4 and the source of the radio frequency power amplifier VT1 are grounded.
[0005] The utility model discloses the beneficial effect is: the utility model discloses an automatic power control of radio frequency power amplifier is realized through adopting current detection technology, has remarkable beneficial effect. First, using general, low -cost component, such as operational amplifier, resistance, capacitor, etc., greatly reduces the overall cost of circuit. Secondly, the circuit design is compact, and the volume is small, and is applicable to the equipment of higher space requirement, especially small -size wireless communication equipment. Thirdly, through real -time monitoring the working current of power amplifier and carries out feedback regulation, ensures the output power stability, can effectively respond to external environmental change (such as temperature fluctuation), improves the reliability and stability of system. The technical scheme simplifies the traditional automatic power control method, has higher practicality and economy. BRIEF DESCRIPTION OF DRAWINGS
[0006] Figure 1 The utility model discloses the circuit principle diagram. DETAILED DESCRIPTION
[0007] The utility model discloses the circuit principle diagram.
[0008] As Figure 1As shown, an automatic power control radio frequency power amplifier circuit based on current detection includes: operational amplifier power input terminal VCC1, radio frequency power amplifier power input terminal VCC2, radio frequency input terminal RFI, radio frequency output terminal RFO, power control voltage input terminal VP, coupling capacitor C1, input matching inductor L1, bias resistor R1, bypass capacitor C2, bypass capacitor C6, filter resistor R2, gain resistor R3, operational amplifier N1A, N1B (N1A and N1B constitute a double operational amplifier chip N1), N1B same direction input resistor R4, N1B reverse input resistor R5, gain resistor R6, bias resistor R7, bias resistor R8, N1A same direction input resistor R9, N1A reverse input resistor R10, current detection resistor R11, bypass capacitor C3, bypass capacitor C4, radio frequency power amplifier VT1, choke inductor L2, coupling capacitor C5, output matching inductor L3. Among them, the operational amplifier power input terminal VCC1 is used to provide power for the operational amplifier N1, the radio frequency power amplifier power input terminal VCC2 is used to provide power for the radio frequency power amplifier VT1, the radio frequency input terminal RFI is used to input the radio frequency signal to be amplified, the radio frequency power amplifier VT1 is used to amplify the radio frequency signal, the current detection resistor R11 is used to detect the working current of the radio frequency power amplifier VT1 and convert it into an error voltage, the operational amplifier N1A, N1B is used to receive the error voltage and the power control voltage VP and generate a feedback bias voltage through differential amplification, the feedback bias voltage is used to adjust the power output of the radio frequency power amplifier VT1, so as to realize automatic power control, the radio frequency output terminal RFO is used to output the amplified radio frequency signal, and the power control voltage input terminal VP is used to input the voltage signal for controlling the power output, so as to control the power level of the radio frequency power amplifier.
[0009] The specific connection of the circuit is as follows: the radio frequency input end RFI is connected with one end of the capacitor C1, the other end of the capacitor C1 is connected with one end of the inductor L1, the other end of the inductor L1 is connected with one end of the resistor R1 and the gate of the radio frequency power amplifier VT1 respectively; the other end of the resistor R1 is connected with one end of the capacitor C2 and one end of the resistor R2 respectively, the other end of the capacitor C2 is grounded, the other end of the resistor R2 is connected with the output end (7th pin of the double operational amplifier chip N1) and the reverse input end (6th pin of the double operational amplifier chip N1) of the operational amplifier N1B and one end of the resistor R5 respectively, the radio frequency input end RFI is connected with one end of the capacitor C1, the other end of the capacitor C1 is connected with one end of the inductor L1, the other end of the inductor L1 is connected with one end of the resistor R1 and the gate of the radio frequency power amplifier VT1 respectively; the other end of the resistor R1 is connected with one end of the capacitor C2 and one end of the resistor R2 respectively, the other end of the capacitor C2 is grounded, the other end of the resistor R2 is connected with the output end (7th pin of the double operational amplifier chip N1) of the operational amplifier N1B and one end of the resistor R3 respectively, the positive power supply end (8th pin of the double operational amplifier chip N1) of the operational amplifier N1B is connected with the operational amplifier power supply input end VCC1 and one end of the capacitor C6 respectively, the other end of the capacitor C6 is grounded; the same input end (5th pin of the double operational amplifier chip N1) of the operational amplifier N1B is connected with the power control voltage input end VP through the resistor R4; the other end of the resistor R3 is connected with the reverse input end (6th pin of the double operational amplifier chip N1) of the operational amplifier N1B and one end of the resistor R5 respectively, the other end of the resistor R5 is connected with the output end (1st pin of the double operational amplifier chip N1) of the operational amplifier N1A and one end of the resistor R6 respectively, the other end of the resistor R6 is connected with the reverse input end (2nd pin of the double operational amplifier chip N1) of the operational amplifier N1A, the resistor R8 and one end of the resistor R10 respectively, the other end of the resistor R8 is grounded, the negative power supply end (4th pin of the double operational amplifier chip N1) of the operational amplifier N1A is grounded, the same input end (3rd pin of the double operational amplifier chip N1) of the operational amplifier N1A is connected with one end of the resistor R7 and one end of the resistor R9 respectively, the other end of the resistor R7 is grounded; the other end of the resistor R9 is connected with one end of the resistor R11, one end of the capacitor C3 and the radio frequency power amplifier power supply input end VCC2 respectively, the other end of the resistor R11 is connected with the other end of the resistor R10, one end of the inductor L2 and one end of the capacitor C4 respectively, the other end of the inductor L2 is connected with the drain of the radio frequency power amplifier VT1 and one end of the capacitor C5 respectively, the other end of the capacitor C5 is connected with the inductor L3, the other end of the inductor L3 is connected with the radio frequency output end RFO; the other ends of the capacitor C3, the capacitor C4 and the source of the radio frequency power amplifier VT1 are grounded.
[0010] The working principle of the utility model is as follows:
[0011] With the example of realizing the working frequency covering the range of 400MHz to 470MHz and the output power of 4W (36dBm), the element parameters are set as follows: the coupling capacitances C1 and C5 are 47pF chip capacitors, the matching inductances L1 and L3 are 4.7nH chip winding inductances, the bypass capacitances C2, C3, C4 and C6 are 0.1uF chip capacitors, the bias resistances R1 and the filter resistance R2 are 1kΩ chip resistors, the gain resistance R3 is 33kΩ chip resistor, the gain resistance R6 is 470kΩ chip resistor, the operational amplifier N1 is chip AD8566ARM, the same direction input resistances R4 and R5 of N1B are 33kΩ chip resistors, the bias resistances R7 and R8 and the same direction input resistances R9 and R10 of N1A are 150kΩ chip resistors, the current detection resistance R11 is 0.15Ω chip resistor, the RF power amplifier VT1 is RF power MOS tube RD07MUS2B, and the choke inductance L2 is 47nH chip winding inductance. The input RF signal power of RFI is 25dBm, the input voltage of VCC1 is 5Vdc, the input voltage of VCC2 is 7.4Vdc, the input voltage of VP is 3.1Vdc, the gain resistance R6, the bias resistances R7 and R8, the same direction input resistances R9 and R10 of N1A, the current detection resistance R11 and the operational amplifier N1A realize the conversion of the working current of the RF power amplifier VT1 into error voltage, the error voltage is input to the reverse input end IN- of the operational amplifier N1B and the VP input to the same direction input end IN+ of N1B to obtain the feedback bias voltage by subtraction, the feedback bias voltage is input to the gate of the MOS tube VT1 to realize power control. When the output power of the RF power amplifier VT1 increases or decreases with the change of external environment such as temperature, the drain current of VT1 will increase or decrease accordingly, and then the error voltage will increase or decrease accordingly, and the feedback bias voltage output by the difference between the error voltage and the VP input voltage through N1B will decrease or increase accordingly, and the power of the MOS tube VT1 is positively correlated with the size of the bias voltage at the gate of the MOS tube VT1, so as to realize the automatic power control of the RF power amplifier circuit.
[0012] The RF power amplifier circuit realizes the automatic power regulation through current detection and feedback control. In the working process, the input RF signal is transmitted into the RF power amplifier circuit through the RF input end RFI, and after the processing of the coupling capacitance C1 and the matching inductance L1, the signal enters the RF power amplifier VT1 for amplification. At this time, the current detection resistance R11 monitors the working current of VT1 and converts it into error voltage through the operational amplifier N1A. The error voltage is input to the reverse input end (IN-) of the operational amplifier N1B and the power control voltage VP input to the same direction input end (IN+) for differential input amplification, and a feedback bias voltage is generated through the output end of the operational amplifier N1B.
[0013] The feedback bias voltage is input to the gate of MOS tube VT1 after adjustment, controlling the working state of VT1, thereby adjusting the output power of the radio frequency power amplifier. When the external environment changes (such as temperature change), causing the output power of the radio frequency power amplifier to change, the drain current of VT1 will increase or decrease accordingly. With the change of current, the error voltage fluctuates, and then adjusts the bias voltage through the feedback control circuit, keeping the output power of VT1 stable. Ultimately, this closed-loop feedback mechanism realizes the automatic control of power, ensuring that the system can always provide stable output power in changing working environment.
Claims
1. An automatic power control radio frequency power amplifier circuit based on current detection, characterized in that, include: The system includes an operational amplifier power input terminal, an RF power amplifier power input terminal, an RF input terminal, an RF output terminal, a power control voltage input terminal, an operational amplifier, an RF power amplifier, coupling capacitors, matching inductors, current sensing resistors, gain resistors, bias resistors, filter resistors, bypass capacitors, and a choke inductor. The operational amplifier power input terminal provides power to the operational amplifier, the RF power amplifier power input terminal provides power to the RF power amplifier, the RF input terminal receives the RF signal, the RF output terminal outputs the amplified RF signal, the power control voltage input terminal controls the power level of the RF power amplifier, and the operational amplifier receives error voltage and power control voltage. The voltage is differentially amplified to generate a feedback bias voltage, which adjusts the power output of the RF power amplifier, which is used to amplify the RF signal. The specific circuit includes an RF input terminal RFI, an RF output terminal RFO, an operational amplifier power input terminal VCC1, an RF power amplifier power input terminal VCC2, a power control voltage input terminal VP, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11, capacitors C1, C2, C3, C4, C5, and C6, and inductors L1, L2, and L3. The RF power amplifier... The dual operational amplifier chip N1, consisting of VT1, operational amplifiers N1A and N1B, is connected as follows: the RF input terminal RFI is connected to one end of capacitor C1; the other end of capacitor C1 is connected to one end of inductor L1; the other end of inductor L1 is connected to one end of resistor R1 and the gate of RF power amplifier VT1; the other end of resistor R1 is connected to one end of capacitor C2 and one end of resistor R2; the other end of capacitor C2 is grounded; the other end of resistor R2 is connected to the output terminal of operational amplifier N1B and one end of resistor R3; the positive power supply terminal of operational amplifier N1B is connected to the operational amplifier power input terminal VCC1 and one end of capacitor C6. The other end is grounded; the non-inverting input of operational amplifier N1B is connected to the power control voltage input VP through resistor R4; the other end of resistor R3 is connected to the inverting input of operational amplifier N1B and one end of resistor R5, the other end of resistor R5 is connected to the output of operational amplifier N1A and one end of resistor R6, the other end of resistor R6 is connected to the inverting input of operational amplifier N1A, one end of resistor R8 and one end of resistor R10, the other end of resistor R8 is grounded, the negative power supply of operational amplifier N1A is grounded, the non-inverting input of operational amplifier N1A is connected to one end of resistor R7 and one end of resistor R9, and the other end of resistor R7 is grounded;The other end of resistor R9 is connected to one end of resistor R11, one end of capacitor C3, and the RF power amplifier input terminal VCC2. The other end of resistor R11 is connected to the other end of resistor R10, one end of inductor L2, and one end of capacitor C4. The other end of inductor L2 is connected to the drain of RF power amplifier VT1 and one end of capacitor C5. The other end of capacitor C5 is connected to inductor L3, and the other end of inductor L3 is connected to the RF output terminal RFO. The other ends of capacitors C3 and C4, and the source of RF power amplifier VT1, are grounded.