Radio frequency front-end module and electronic device with current protection function

Abstract

The present invention provides a radio frequency front-end module and electronic device with current protection function. [Solution] The radio frequency front-end module includes an input matching module, a power amplifier, an output matching module, a power module and a protection unit, where the input end of the input matching module is connected to the input end of an external radio frequency signal, and the output end of the input matching module is connected to the input end of the power amplifier. The output end of the power amplifier is connected to the input end of the output matching module, and the output end of the output matching module is connected to the output end of the radio frequency signal, and the output ends of the power module and the protection unit are respectively connected to the power amplifier. The protection unit plays the role of current protection, voltage protection and power protection for the power amplifier of the radio frequency front-end module, thereby improving the reliability and safety of the radio frequency front-end module operating in harsh environments.

Description

[Technical field]

[0001] The present invention belongs to the technical field of radio frequency integrated circuits, and relates to a radio frequency front-end module with current protection function, and also to an electronic device equipped with the radio frequency front-end module. [Background technology]

[0002] With the continuous development of integrated circuit technology, modern electronic devices have higher requirements for radio frequency front-end modules, especially in the situation of operating in harsh environments. For example, the rise or fall of the temperature of the operating environment reaches or exceeds the limit of the required temperature range (the general temperature range of -25℃~85℃ or -40℃~110℃). For power components, operating under high or low temperature environment will reduce the safe operating area of ​​the power components, and if the operating current applied to the power components exceeds the maximum withstand current of the components, it may cause irreversible damage or destruction of the power components. Therefore, in order to ensure the normal operation of power components, it is necessary to ensure that the power components always operate in the safe operating area in harsh environmental situations by adopting appropriate protection measures to limit the excessive operating current of the power components.

[0003] As shown in Figure 1, a typical radio frequency front-end module in the prior art includes an input matching module, a power amplifier (abbreviated as PA), an output matching module and a power supply module. Here, the power amplifier usually includes a two-stage or three-stage power amplification unit and is the main power component for current protection.

[0004] US Patent Application No. US2009256637A1 discloses a high frequency power amplifier. Here, the high frequency power amplifier circuit of the fourth embodiment includes a high frequency power amplifier transistor, a matching circuit, a bias power transistor, and a passive element. Here, the passive element is connected between a common power terminal and a collector of the bias power transistor connected to the first stage transistor. The passive element is realized by a resistor and an inductor connected in series. In this high frequency power amplifier circuit, the passive element improves the linearity at high output by preventing the power drop of the bias power transistor. Summary of the Invention [Problem to be solved by the invention]

[0005] The technical problem to be solved by the present invention is to provide a radio frequency front-end module with a current protection function.

[0006] Another technical problem that the present invention aims to solve is to provide an electronic device that includes this radio frequency front-end module. [Means for solving the problem]

[0007] To achieve the above objectives, the present invention adopts the following technical solutions:

[0008] According to a first aspect of an embodiment of the present invention, there is provided a radio frequency front-end module with current protection function, comprising an input matching module, a power amplifier, an output matching module, a power supply module and a protection unit.

[0009] Here, the input end of the input matching module is connected to the input end of an external radio frequency signal, and the output end is connected to the input end of the power amplifier to realize impedance matching between the power amplifier and the input end of the external radio frequency signal.

[0010] The output end of the power amplifier, which amplifies the power of an input radio frequency signal, is connected to the input end of the output matching module.

[0011] The output of the power matching module is connected to an output of a radio frequency signal to realize power matching between the power amplifier and the output of the radio frequency signal.

[0012] The output end of the protection unit is connected to the power amplifier, and limits the current of the power amplifier with a threshold voltage generated by the protection unit to realize current protection.

[0013] Preferably, the protection unit comprises at least a current limiting resistor and a filter capacitor, where the current limiting resistor is used to generate the threshold voltage and the filter capacitor exhibits a low resistance state at radio frequency and envelope signal frequencies such that the threshold voltage does not vary with the radio frequency signal and envelope signal.

[0014] Preferably, the protection unit further comprises a trap circuit connected in parallel with the filter capacitor.

[0015] Preferably, the power amplifier includes at least one stage of a power amplification unit, the power amplification unit including a bias circuit and a power amplification circuit, and the protection unit is connected to the bias circuit of the at least one stage of the power amplification unit.

[0016] Preferably, the bias circuit comprises a first transistor, a second transistor, a third transistor, a first bias resistor and a first filter capacitor, the power amplifier circuit comprises a fourth transistor, a first ballast resistor and a first inductor, and the protection unit comprises a first current limiting resistor and a second filter capacitor.

[0017] Here, the emitter of the third transistor is connected to the ground potential terminal, and the base and collector of the third transistor are short-circuited and then connected to the emitter of the second transistor. The base and collector of the second transistor are short-circuited and then connected to the first bias resistor on one side, and to the base of the first transistor and the first filter capacitor on the other side. The other end of the first bias resistor is connected to a bias power supply, and the other end of the first filter capacitor is connected to a ground potential terminal. The collector of the first transistor is connected to the second filter capacitor and the first current limiting resistor, the other end of the second filter capacitor is connected to a ground potential terminal, and the other end of the first current limiting resistor is connected to a second power supply terminal. The emitter of the first transistor is connected to the first ballast resistor, and the other end of the first ballast resistor is connected to an input terminal on one side, and to the base of the fourth transistor on the other side. The emitter of the fourth transistor is connected to a ground potential terminal, the collector of the fourth transistor is connected to an output terminal on one side and to the first inductor on the other side, and the other end of the first inductor is connected to a first power supply terminal.

[0018] Preferably, when the bias circuit, the power amplifier circuit and the protection unit satisfy the following formula, the bias circuit and the power amplifier circuit are in a current limit protection operation state. V 1C <V 1b -V th_bc V 1C =VDD-V R V R =I1*R

[0019] Here, V 1C is the collector voltage of the first transistor, and V 1b is the base voltage of the first transistor. V th_bc is the threshold voltage between the base and collector of the first transistor, and V Ris the voltage drop across the first current limiting resistor. I1 is the collector current of the first transistor, R is the resistance of the first current limiting resistor, and VDD is the voltage of the second power supply.

[0020] Preferably, the current limiting resistor in the protection unit uses a thermistor having a temperature coefficient. For the power amplifier that is easily burned at low temperatures, the current limiting resistor uses a thermistor having a negative temperature coefficient, and for the power amplifier that is easily burned at high temperatures, the current limiting resistor uses a thermistor having a positive temperature coefficient.

[0021] Preferably, the filter capacitor in the protection unit uses multiple capacitors of different sizes with capacitance values ​​ranging from pF level to uF level to filter out radio frequency signals and envelope signals of different frequencies and achieve wideband filtering.

[0022] Preferably, the power supply connected to the first current limiting resistor in the protection unit uses a constant voltage source having a temperature coefficient, and for the power amplifier that is prone to burn out at low temperatures, the power supply uses a constant voltage source having a positive temperature coefficient, and for the power amplifier that is prone to burn out at high temperatures, the power supply uses a constant voltage source having a negative temperature coefficient.

[0023] Preferably, the protection unit further includes a trap circuit configured by connecting an inductor and a capacitor in parallel, the trap circuit being connected in parallel with the second filter capacitor, where an inductor end of the trap circuit is connected to a node end of the first current limiting resistor and the second filter capacitor, and a capacitor end of the trap circuit is connected to a ground potential end.

[0024] Preferably, the protection unit further comprises an inductor, which forms an RLC combination circuit with the current limiting resistor and the filter capacitor, to further filter out radio frequency signals and envelope signals.

[0025] Preferably, the RLC combination circuit includes an eleventh inductor, a current limiting resistor, an eleventh capacitor and a twelfth capacitor.

[0026] Here, one end of the current limiting resistor is connected to the collector of a first transistor in a bias circuit, and is connected to an eleventh capacitor on the other hand. The other end of the current limiting resistor is connected to the eleventh inductor, and is connected to the twelfth capacitor on the other hand. The other end of the eleventh inductor is connected to a second power supply terminal, and the other ends of the eleventh capacitor and the twelfth capacitor are each connected to a ground potential terminal.

[0027] Preferably, the power supply further comprises a control switch, the control switch being connected in parallel to both ends of the protection unit to realize the input or output of the protection unit, and the control signal end of the control switch being connected to the first power supply end or the output end of the power detection circuit.

[0028] According to a second aspect of an embodiment of the present invention, there is provided an electronic device including a radio frequency front-end module having the above current protection function.

[0029] Compared with the prior art, the radio frequency front-end module with current protection function provided by the embodiment of the present invention can play the role of overcurrent protection, overvoltage protection and overpower protection for the power amplifier by adding a protection unit, thereby greatly improving the reliability and safety of the radio frequency front-end module operating in harsh environments. At the same time, the protection unit only uses the change in the voltage drop of the current limiting resistor to realize the threshold voltage, does not introduce additional circuit power consumption, and does not occupy a large circuit area, so the radio frequency front-end module with current protection function provided by the present invention has the beneficial effects of original and reasonable structural design, low design cost, high reliability and excellent circuit performance, and is applicable to radio frequency front-end modules of various structures. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is a block diagram showing the structure of an exemplary radio frequency front-end module in the prior art. [Diagram 2] A block diagram showing the structure of a radio frequency front-end module with current protection function provided by an embodiment of the present invention. [Diagram 3] 1 is a schematic diagram showing the structures of a power amplifier, a power supply module, and a protection unit in a first embodiment of the present invention. [Figure 4a] FIG. 2 is a schematic diagram showing circuits of an amplification unit and a protection unit in the first embodiment of the present invention. [Figure 4b] FIG. 4 is a schematic diagram showing another circuit of the amplification unit and the protection unit in the first embodiment of the present invention. [Diagram 5] FIG. 2 is a schematic diagram showing a structure in which a protection unit provides overcurrent protection for the last two stages of a power amplification unit in a first embodiment of the present invention. [Figure 6] 1 is a schematic diagram showing a structure in which a protection unit provides overcurrent protection for the final stage of a power amplification unit in a first embodiment of the present invention. [Figure 7] FIG. 11 is a schematic diagram showing circuits of an amplification unit and a protection unit in a second embodiment of the present invention. [Figure 8] FIG. 11 is a schematic diagram showing the structures of a power amplifier, a power supply module, and a protection unit in a second embodiment of the present invention. [Figure 9] FIG. 11 is a schematic diagram showing a structure in which a protection unit provides overcurrent protection for the last two stages of a power amplification unit in a second embodiment of the present invention. [Figure 10] FIG. 11 is a schematic diagram showing a structure in which a protection unit provides overcurrent protection for the final stage of a power amplification unit in a second embodiment of the present invention. [Figure 11] FIG. 11 is a schematic diagram showing circuits of an amplification unit and a protection unit in a third embodiment of the present invention. [Figure 12] FIG. 11 is a schematic diagram showing a first structure of a protection unit with a control switch in a third embodiment of the present invention. [Figure 13] FIG. 11 is a schematic diagram showing a second structure of the protection unit with a control switch in the third embodiment of the present invention. [Figure 14] 2 is a graph showing the relationship between the input power and the output current of a power amplifier circuit in the technical solution provided by an embodiment of the present invention; [Figure 15] FIG. 1 illustrates an electronic device using a radio frequency front-end module provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, the technical contents of the present invention will be described in detail and specifically with reference to the accompanying drawings and specific embodiments.

[0032] As shown in Figure 2, the radio frequency front-end module with current protection function provided by the embodiment of the present invention includes an input matching module 1, a power amplifier 2, an output matching module 3, a power supply module 4 and a protection unit 5. Here, the input end of the input matching module 1 is connected to the input end PA IN of the external radio frequency signal, and the output end of the input matching module 1 is connected to the input end of the power amplifier 2. The output end of the power amplifier 2 is connected to the input end of the output matching module 3, and the output end of the output matching module 3 is connected to the output end PA OUT of the radio frequency signal. The power supply module 4 and the protection unit 5 are respectively connected to the power amplifier 2.

[0033] The input matching module 1 is used to realize impedance matching between the power amplifier 2 and the input end PA IN of the radio frequency signal. The power amplifier 2 is used for power amplification of the input radio frequency signal and comprises at least one stage of a power amplification unit. The power amplification unit comprises a bias circuit and a power amplification circuit. The output matching module 3 is used to realize power matching between the power amplifier 2 and the output end PA OUT of the radio frequency signal. The power supply module 4 supplies the power amplifier 2 with the bias current and voltage required for operation. The protection unit 5 provides current protection for the power amplifier 2 and is connected to the bias circuit of the at least one stage of the power amplification unit. The protection unit 5 comprises at least one current limiting resistor and a filter capacitor.

[0034] The power supply VCC supplies a power supply voltage and a current to the power amplifier, and the power supply VDD supplies a power supply voltage and a current to a bias circuit in the power amplifier and to the power supply module 4. Usually, both the power supply VCC and the power supply VDD are supplied from an external power supply module.

[0035] In the first embodiment of the present invention, the specific circuits of the power amplifier 2, the power supply module 4, and the protection unit 5 are as shown in FIG. 3. Here, the power amplifier 2 includes three power amplifier units, a first-stage power amplifier unit PA1, a second-stage power amplifier unit PA2, and a third-stage power amplifier unit PA3, and the three power amplifier units are sequentially cascaded. The first power supply Vreg1, the second power supply Vreg2, and the third power supply Vreg3 output from the power supply module 4 are connected to the bias power supply terminals of the first-stage power amplifier unit PA1, the second-stage power amplifier unit PA2, and the third-stage power amplifier unit PA3, respectively. The protection unit 5 has one end connected to the power supply VDD, and the other end connected to the bias circuits of the first-stage power amplifier unit PA1, the second-stage power amplifier unit PA2, and the third-stage power amplifier unit PA3, respectively.

[0036] In the first embodiment of the present invention, the circuit structure of the power amplification unit and the protection unit of any one of the three-stage power amplification units is as shown in FIG. 4a. The power amplification unit includes a bias circuit and a power amplification circuit. The bias circuit includes a first transistor HBT1, a second transistor HBT2, a third transistor HBT3, a first bias resistor R1 and a first filter capacitor C1. The power amplification circuit includes a fourth transistor HBT4, a first ballast resistor R2 and a first inductor L1. The protection unit includes a first current limiting resistor R and a second filter capacitor C. Here, the second transistor HBT2 and the third transistor HBT3 form a double diode. The emitter of the third transistor HBT3 is connected to the ground potential end, and the base and collector of the third transistor HBT3 are short-circuited and then connected to the emitter of the second transistor HBT2. The base and collector of the second transistor HBT2 are short-circuited and then connected to the first bias resistor R1 on one side, and to the base of the first transistor HBT1 and the first filter capacitor C1 on the other side. The other end of the first bias resistor R1 is connected to the bias power supply Vreg, and the other end of the first filter capacitor C1 is connected to the ground potential end. The collector of the first transistor HBT1 is connected to the second filter capacitor C and the first current limiting resistor R, and the other end of the second filter capacitor C is connected to the ground potential end, and the other end of the first current limiting resistor R is connected to the power supply VDD. The emitter of the first transistor HBT1 is connected to the first ballast resistor R2, and the other end of the first ballast resistor R2 is connected to the input terminal IN on one side, and to the base of the fourth transistor HBT4 on the other side. The emitter of the fourth transistor HBT4 is connected to the ground potential terminal, and the collector of the fourth transistor HBT4 is connected to the output terminal OUT on one side and to the first inductor L1 on the other side, and the other end of the first inductor L1 is connected to the power supply VCC.

[0037] The operating principle of the radio frequency front-end module with current protection function in the above first embodiment to realize current protection is as follows.

[0038] As shown in FIG. 4a, during normal operation, the bias circuit, the power amplifier circuit and the protection unit satisfy the following equation: I2 ≒ β * I1 (1) V R =I1*R (2) V 1C =VDD-V R (3) V 1C >V 1b -V th_bc (4)

[0039] Here, V 1C is the collector voltage of the first transistor HBT1, and V 1b is the base voltage of the first transistor HBT1, and V th_bc is the threshold voltage between the base and collector of the first transistor HBT1, and V R is the voltage drop in the first current limiting resistor R, I1 is the collector current of the first transistor HBT1, I2 is the collector current of the fourth transistor HBT4, R is the resistance value of the first current limiting resistor R, β is the amplification coefficient of the fourth transistor HBT4, and VDD is the voltage value of the power supply VDD. At this time, the bias circuit and the power amplifier circuit are not in the current limiting protection state, and Equation 4 is the operation start condition of the first transistor HBT1.

[0040] According to Equation 1, when the external circuit increases the current I2 of the fourth transistor HBT4, the first transistor HBT1 needs to supply a larger output current I1. At this time, according to Equation 2 and Equation 3, the increase in current I1 causes a voltage drop V across the first current limiting resistor R. R becomes large, and the collector voltage V of the first transistor HBT1 1C V 1C V 1C <V 1b -V th_bc When the voltage V drops to 1 V, the current I1 drops sharply, and the current I2 also drops accordingly, thus providing the overcurrent protection effect for the circuit. 1C <V1b -V th_bc When V is 1, the bias circuit and the power amplifier circuit enter the current limit protection operation state. th_bc is 1.2V, and V 1b is 2.4V, so V 1C <1.2V, the bias circuit and power amplifier circuit will enter current limit protection operation state.

[0041] Voltage drop V across the first current limiting resistor R in the protection unit R is used as a threshold voltage to limit the maximum current of the power amplifier circuit, thereby realizing the current protection function. The second filter capacitor C performs a filtering effect, presenting a low resistance state at the radio frequency and envelope signal frequency, and the voltage drop V across the first current limiting resistor R R does not vary with changes in the radio frequency signal and the envelope signal, ensuring that the first transistor HBT1 is in a stable operating state.

[0042] As shown in FIG. 4b, the protection unit in the above embodiment can add a trap circuit, which is composed of a second inductor L2 and a third capacitor C4 connected in parallel. The trap circuit is connected in parallel to a second filter capacitor C. Here, the inductor (L2) end is connected to the node end of the first current limiting resistor R and the second filter capacitor C, and the capacitor end (C4) is connected to the ground potential end. The trap circuit and the second filter capacitor are used together to suppress radio frequency and envelope signal frequencies, and can realize the filtering out of radio frequency signals and envelope signals by presenting a low resistance state at radio frequency and envelope signal frequencies, and can also realize the effect of wideband filtering.

[0043] The technical solution provided by the above first embodiment may have different modifications of the circuit structures of the power amplifier, power supply module and protection unit shown in Figure 3 according to different requirements for circuit performance. For example, the power amplifier is not limited to a cascade of three-stage power amplification units, but may be a cascade of one-stage, two-stage or even multi-stage power amplification units to realize the technical solution provided by the present invention. The bias circuit shown in Figure 4a and Figure 4b may have different modifications according to actual needs, and is not limited herein.

[0044] In addition, in the technical solution shown in FIG. 3, the protection unit provides overcurrent protection for all three stages of power amplification units. As shown in FIG. 5, the protection unit can also provide overcurrent protection only for the last two stages of power amplification units, where the output terminals of the protection unit are respectively connected to the bias circuits of the last two stages of power amplification units PA2 and PA3. As shown in FIG. 6, the protection unit can also provide overcurrent protection only for the last stage of the power amplification units, where the output terminals of the protection unit are connected to the bias circuit of the last stage of power amplification unit PA3.

[0045] According to the actual needs of the power amplifier circuit, the filter capacitor in the protection unit is not limited to using one capacitor, but can also include multiple capacitors of different sizes, whose capacitance values ​​are from pF level to uF level, so as to realize the effect of wideband filtering by filtering out radio frequency signals of different frequencies.

[0046] In the second embodiment of the present invention, for the situation where a large increase or decrease in temperature of the operating environment causes damage or destruction of power components, the power amplifier 2, the power supply module 4 and the protection unit 5 in the radio frequency front-end module can adopt the following two technical solutions to solve the problem of overcurrent protection:

[0047] As shown in Figure 7, the protection unit in the first technical solution is composed of a first current limiting resistor R and a second filter capacitor C. Here, the first current limiting resistor R uses a thermistor with a temperature coefficient. For the power amplifier circuit that is easy to burn out at low temperatures, the first current limiting resistor R selects a thermistor with a negative temperature coefficient, and for the power amplifier circuit that is easy to burn out at high temperatures, the first current limiting resistor R selects a thermistor with a positive temperature coefficient. Specifically, the working principle of realizing overcurrent protection is as follows:

[0048] If the circuit is a power amplifier circuit that is prone to burning at low temperatures and the first current limiting resistor R is a thermistor with a negative temperature coefficient, the resistance value of the first current limiting resistor R increases as the temperature decreases. In this case, the voltage drop V of the first current limiting resistor R is calculated according to Equation 1, Equation 2, and Equation 3. R becomes large, and the collector voltage V of the first transistor HBT1 1C becomes smaller. V 1C V 1C <V 1b -V th_bc When the temperature drops to 100° C., the current I1 drops sharply, and the current I2 drops accordingly, providing an overcurrent protection effect for the power amplifier circuit, which is prone to burnout at low temperatures. In addition, by using a thermistor with a negative temperature coefficient as the first current limiting resistor, as opposed to a normal resistor, the protection start time can be shortened and the protective effect can be further strengthened.

[0049] If the circuit is a power amplifier circuit that is prone to burning at high temperatures and the first current limiting resistor R is a thermistor with a positive temperature coefficient, the resistance value of the first current limiting resistor R increases as the temperature rises. At this time, the voltage drop V of the first current limiting resistor R is calculated according to Equation 1, Equation 2, and Equation 3. R becomes large, and the collector voltage V of the first transistor HBT1 1C becomes smaller. V 1C V 1C <V 1b -V th_bcWhen the first current limiting resistor is reduced to 100V, the current I1 is rapidly reduced, and the current I2 is reduced accordingly, thereby providing an overcurrent protection effect for the power amplifier circuit, which is prone to burnout at high temperatures. In addition, by using a thermistor having a positive temperature coefficient as the first current limiting resistor, as opposed to a normal resistor, the protection start time can be shortened and the protection effect can be further enhanced.

[0050] As shown in Figure 8, the bias power supply Vreg4 in the second technical solution is a bias power supply with a temperature coefficient output from the power supply module, which supplies power to the bias circuits of all three stages of the power amplifier unit through the protection unit. For the power amplifier circuit that is prone to burn out at low temperatures, the bias power supply Vreg4 selects a constant voltage source with a positive temperature coefficient, and for the power amplifier circuit that is prone to burn out at high temperatures, the bias power supply Vreg4 selects a constant voltage source with a negative temperature coefficient. The working principle of the overcurrent protection is as follows:

[0051] If the circuit is a power amplifier circuit that is prone to burning at low temperatures and the bias power supply Vreg4 is a constant voltage source with a positive temperature coefficient, the voltage output of the bias power supply Vreg4 will decrease as the temperature decreases. At this time, the collector voltage V of the first transistor HBT1 is calculated by Equation 1 and Equation 3 (where VDD is replaced with Vreg4). 1C V 1C V 1C <V 1b -V th_bc When the temperature of the bias power supply Vreg4 is reduced to 100V, the current I1 is rapidly reduced, and the current I2 is reduced accordingly, thereby realizing an overcurrent protection effect for the power amplifier circuit that is prone to burnout at low temperatures. In addition, compared with the constant power supply VDD, the bias power supply Vreg4 is a constant voltage source having a positive temperature coefficient, thereby shortening the protection start time and strengthening the protection.

[0052] If the circuit is a power amplifier circuit that is prone to burning at high temperatures and the bias power supply Vreg4 is a constant voltage source with a negative temperature coefficient, the voltage output of the bias power supply Vreg4 will decrease as the temperature rises. In this case, the collector voltage V of the first transistor HBT1 is calculated by Equation 1 and Equation 3 (where VDD is replaced with Vreg4). 1C becomes smaller. V 1C V 1C <V 1b -V th_bc When the temperature of the bias power supply Vreg4 is reduced to 100V, the current I1 is rapidly reduced, and the current I2 is reduced accordingly, thereby realizing an overcurrent protection effect for the power amplifier circuit that is easily burned out at high temperatures. In addition, compared with the constant power supply VDD, the bias power supply Vreg4 is a constant voltage source having a negative temperature coefficient, thereby shortening the protection start time and strengthening the protection.

[0053] In the technical solution provided in the above second embodiment, the circuit structures of the power amplifier, the power supply module and the protection unit may have different modifications according to different needs for circuit performance. For example, the power amplifier is not limited to being configured by cascading three-stage power amplification units, but can also be configured by cascading one-stage, two-stage, or even multi-stage power amplification units to realize the technical solution provided by the present invention.

[0054] In addition, the protection unit in the technical solution shown in FIG. 8 provides overcurrent protection for all three stages of the power amplification units. As shown in FIG. 9, the protection unit can also provide overcurrent protection for only the last two stages of the power amplification units. Here, the protection unit is composed of a first current limiting resistor and a second filter capacitor, one end of the first current limiting resistor and the second filter capacitor are respectively connected to the bias circuits of the last two stages of the power amplification units PA2 and PA3, and the other end of the first current limiting resistor is connected to a bias power supply Vreg4 having a temperature coefficient. As shown in FIG. 10, the protection unit can provide overcurrent protection for only the power amplification unit of the last stage. Here, the protection unit is composed of a first current limiting resistor and a second filter capacitor, one end of the first current limiting resistor and the second filter capacitor are respectively connected to the bias circuit of the power amplification unit PA3 of the last stage, and the other end of the first current limiting resistor is connected to a bias power supply Vreg4 having a temperature coefficient.

[0055] In the third embodiment of the present invention, as shown in FIG. 11, when there is a problem with the radio frequency impedance matching and affects the performance of the circuit, the protection unit in the radio frequency front-end module can be realized by adopting an RLC combination circuit. The RLC combination circuit is composed of an eleventh inductor L, an eleventh resistor R (i.e., a current limiting resistor), an eleventh capacitor C2 and a twelfth capacitor C3. Here, one end of the eleventh resistor R is connected to the collector of the first transistor HBT1 of the bias circuit on the one hand, and to the eleventh capacitor C2 on the other hand. The other end of the eleventh resistor R is connected to the eleventh inductor L on the one hand, and to the twelfth capacitor C3 on the other hand. The other end of the eleventh inductor L is connected to the power supply VDD. The other ends of the eleventh capacitor C2 and the twelfth capacitor C3 are respectively connected to the ground potential end.

[0056] The eleventh resistor R in the above RLC combination circuit is a current limiting resistor, and the eleventh capacitor C2 and the twelfth capacitor C3 are both filter capacitors. It should be noted that the RLC combination circuit may have other combination forms, but it includes at least one current limiting resistor and one filter capacitor.

[0057] In addition, the RLC combination circuit can realize the input and output of the protection unit through a control switch SW, and the control switch SW can be turned on to limit the current under high power or high current or high voltage, so that the RLC combination circuit does not affect the operating performance of the power amplifier under normal circumstances.

[0058] As shown in Figure 12, the protection unit is realized by adopting an RLC combination circuit, a control switch SW is connected in parallel to both ends of the RLC combination circuit, and the control signal end of the control switch SW is connected to the power supply VCC3. During normal operation, the control switch SW is closed, so the protection unit is released from the operating state and does not affect the operating performance of the power amplifier. When the voltage of the power supply VCC3 increases and reaches a certain threshold, the control switch SW is disconnected, which activates the RLC combination circuit to limit and protect the circuit from overvoltage.

[0059] As shown in Figure 13, the protection unit is realized by adopting an RLC combination circuit, a control switch SW is connected in parallel to both ends of the RLC combination circuit, and the control signal end of the control switch SW is connected to the output end of the power detection circuit Vdet. During normal operation, the control switch SW is closed, so the protection unit is released from the working state and does not affect the working performance of the power amplifier. When the output power of the power detection circuit Vdet becomes large and reaches a certain threshold, the control switch SW is disconnected and the RLC combination circuit enters the working state, thus playing the role of limiting and protecting the overpower of the circuit.

[0060] The technical solution provided by the above third embodiment can be similarly applied to the circuit structures of the first and second embodiments according to the needs of specific circuits. The control switch SW can be connected in parallel to both ends of the protection unit to realize the input and release of the protection unit, thereby playing a role in optimizing the protection function and operating performance of the circuit.

[0061] In order to verify the technical effect of the radio frequency front-end module provided by the embodiment of the present invention, the inventors conducted a simulation test of the input power and output current of the technical solution of the present invention and the conventional technical solution (without a protection unit). The test results are shown in Figure 14, where the abscissa is the input power and the ordinate is the output current. As can be seen from Figure 14, when the input power is continuously increased, the output current in the power amplifier circuit of the conventional technical solution increases continuously with the increase of the input power. In contrast, in the power amplifier circuit with current protection function provided by the present invention, when the input power is continuously increased, the output current is always limited to about 800mA, so that the overcurrent protection of the power amplifier circuit is realized.

[0062] The radio frequency front-end module with current protection function provided in the present invention can be used in electronic devices as an important part of communication components. The electronic devices referred to in this specification refer to computer devices that can be used in mobile environments and support various communication methods such as GSM, EDGE, TD_SCDMA, TDD_LTE, FDD_LTE, 5G, etc., including mobile phones, notebook computers, tablet computers, in-vehicle computers, etc. In addition, the technical solution provided in the present invention can also be applied to other applications of radio frequency integrated circuits, such as communication base stations, intelligent network vehicles, etc.

[0063] As shown in FIG. 15, the electronic device includes at least a processor, a communication component, and a memory, and may further include a sensor component, a power component, a multimedia component, and an input / output interface according to actual needs. Here, the memory, the communication component, the sensor component, the power component, the multimedia component, and the input / output interface are all connected to the processor. The memory may be a static random access memory (SRAM), an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a programmable read-only memory (PROM), a read-only memory (ROM), a magnetic memory, a flash memory, etc. The processor may be a central processing unit (CPU), a graphic processor (GPU), a field programmable logic gate array (FPGA), an application specific integrated circuit (ASIC), a digital signal processing (DSP) chip, etc. Other communication components, sensor components, power components, multimedia components, etc. may be realized using general-purpose components and will not be specifically described in this specification.

[0064] As can be seen from the specific description of the technical solution of the present invention according to the above embodiment, compared with the prior art, the radio frequency front-end module with current protection function provided by the embodiment of the present invention can play the role of overcurrent protection, overvoltage protection and overpower protection of the power amplifier by adding a protection unit, thereby greatly improving the reliability and safety of the radio frequency front-end module operating in harsh environments. At the same time, the protection unit only uses the change in the voltage drop of the current limiting resistor to realize the threshold voltage, does not introduce additional circuit power consumption, and does not occupy a large circuit area, so that the radio frequency front-end module with current protection function provided by the present invention has beneficial effects such as original and reasonable structural design, low design cost, high reliability, and excellent circuit performance, and is suitable for radio frequency front-end modules of various structures.

[0065] It should be noted that the above embodiments are merely examples, and the technical solutions of each embodiment may be combined, all of which are within the protection scope of the present invention.

[0066] Additionally, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying a relative importance or number of technical features depicted. Thus, features defined with the terms "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "plurality" means two or more, unless expressly and specifically limited.

[0067] The above is a detailed description of the radio frequency front-end module and electronic device with current protection function provided by the present invention. Any obvious modifications made to the present invention by those skilled in the art without departing from the practical content of the present invention will be considered as infringement of the patent right of the present invention and will bear the corresponding legal liability.

Claims

1. A radio frequency front-end module with current protection function, comprising an input matching module, a power amplifier, an output matching module and a power supply module, Further comprising a protection unit, The input end of the input matching module is connected to the input end of an external radio frequency signal, and the output end is connected to the input end of the power amplifier to realize impedance matching between the power amplifier and the input end of the external radio frequency signal; The power amplifier is used for power amplifying an input radio frequency signal, and an output terminal of the power amplifier is connected to an input terminal of the output matching module; The output end of the output matching module is connected to the output end of a radio frequency signal to realize power matching between the power amplifier and the output end of the radio frequency signal; A radio frequency front-end module with current protection function, characterized in that an output end of the protection unit is connected to the power amplifier to realize current protection by limiting the current of the power amplifier through a threshold voltage generated by the protection unit.

2. The protection unit comprises at least a current limiting resistor and a filter capacitor; 2. The radio frequency front-end module with current protection function as claimed in claim 1, wherein the current limiting resistor is used to generate the threshold voltage, and the filter capacitor exhibits a low resistance state at radio frequency and envelope signal frequencies such that the threshold voltage does not change with the radio frequency signal and envelope signal.

3. 3. The radio frequency front-end module with current protection function as claimed in claim 2, wherein the protection unit further comprises a trap circuit connected in parallel with the filter capacitor.

4. 2. The radio frequency front-end module with current protection function as claimed in claim 1, characterized in that the power amplifier comprises at least one stage of a power amplification unit, the power amplification unit comprises a bias circuit and a power amplification circuit, and the protection unit is connected to the bias circuit of the at least one stage of the power amplification unit.

5. the bias circuit comprises a first transistor, a second transistor, a third transistor, a first bias resistor and a first filter capacitor; the power amplifier circuit comprises a fourth transistor, a first ballast resistor and a first inductor; the protection unit comprises a first current limiting resistor and a second filter capacitor; The emitter of the third transistor is connected to the ground potential terminal, the base and collector of the third transistor are short-circuited and then connected to the emitter of the second transistor, the base and collector of the second transistor are short-circuited and then connected to the first bias resistor on one side and to the base of the first transistor and the first filter capacitor on the other side, the other end of the first bias resistor is connected to a bias power supply, the other end of the first filter capacitor is connected to the ground potential terminal, the collector of the first transistor is connected to the second filter capacitor and the first current limiting resistor, 5. The radio frequency front-end module with current protection function according to claim 4, wherein the other end of the filter capacitor is connected to a ground potential terminal, the other end of the first current limiting resistor is connected to a second power supply terminal, the emitter of the first transistor is connected to the first ballast resistor, the other end of the first ballast resistor is connected to an input terminal on the one hand and to a base of the fourth transistor on the other hand, the emitter of the fourth transistor is connected to a ground potential terminal, the collector of the fourth transistor is connected to an output terminal on the one hand and to the first inductor on the other hand, and the other end of the first inductor is connected to a first power supply terminal.

6. When the bias circuit, the power amplifier circuit, and the protection unit satisfy the following formula, the bias circuit and the power amplifier circuit are in a current limit protection operation state: V １Ｃ <V １ｂ -V ｔｈ＿ｂｃ V １Ｃ =VDD-V Ｒ V Ｒ =I １ *R Here, V １Ｃ is the collector voltage of the first transistor, and V １ｂ is the base voltage of the first transistor, and V ｔｈ＿ｂｃ is the threshold voltage between the base and collector of the first transistor, and V Ｒ is the voltage drop across the first current limiting resistor, and I １ 6. The radio frequency front end module with current protection function as claimed in claim 5, wherein: R is the collector current of the first transistor, R is the resistance value of the first current limiting resistor, and VDD is the voltage of the second power supply.

7. 3. The radio frequency front-end module with current protection function as claimed in claim 2, characterized in that the current limiting resistor in the protection unit uses a thermistor with a temperature coefficient, and for the power amplifier that is prone to burning out at low temperatures, the current limiting resistor uses a thermistor with a negative temperature coefficient, and for the power amplifier that is prone to burning out at high temperatures, the current limiting resistor uses a thermistor with a positive temperature coefficient.

8. The radio frequency front-end module with current protection function as claimed in claim 2, characterized in that the filter capacitor in the protection unit uses multiple capacitors of different sizes to filter out radio frequency signals and envelope signals of different frequencies and achieve wideband filtering.

9. 6. The radio frequency front-end module with current protection function as claimed in claim 5, characterized in that the power supply connected to the first current limiting resistor in the protection unit uses a constant voltage source with a temperature coefficient, and for the power amplifier that is prone to burning out at low temperatures, the power supply uses a constant voltage source with a positive temperature coefficient, and for the power amplifier that is prone to burning out at high temperatures, the power supply uses a constant voltage source with a negative temperature coefficient.

10. 6. The radio frequency front-end module with current protection function according to claim 5, wherein the protection unit further comprises a trap circuit configured by connecting an inductor and a capacitor in parallel, the trap circuit being connected in parallel with the second filter capacitor, an inductor end of the trap circuit being connected to a node end of the first current limiting resistor and the second filter capacitor, and a capacitor end of the trap circuit being connected to a ground potential end.

11. 3. The radio frequency front-end module with current protection function as claimed in claim 2, wherein the protection unit further comprises an inductor which, together with the current limiting resistor and the filter capacitor, forms an RLC combination circuit for further filtering out radio frequency signals and envelope signals.

12. the RLC combination circuit includes an eleventh inductor, a current limiting resistor, an eleventh capacitor and a twelfth capacitor; 12. The radio frequency front-end module with current protection function according to claim 11, characterized in that one end of the current limiting resistor is connected to the collector of a first transistor in a bias circuit on the one hand and to an eleventh capacitor on the other hand, the other end of the current limiting resistor is connected to the eleventh inductor on the one hand and to the twelfth capacitor on the other hand, the other end of the eleventh inductor is connected to a second power supply terminal, and the other ends of the eleventh capacitor and the twelfth capacitor are each connected to a ground potential terminal.

13. The radio frequency front end module with current protection function as claimed in claim 1, further comprising a control switch, the control switch being connected in parallel to both ends of the protection unit to realize the input or output of the protection unit, and the control signal end of the control switch being connected to the first power supply end or the output end of the power detection circuit.

14. 14. An electronic device comprising a radio frequency front-end module with a current protection function according to any one of claims 1 to 13.

Images