Handheld device

Abstract

The application discloses a handheld device. The handheld device comprises a control chip, a radio frequency read-write chip, a radio frequency front-end circuit and a power supply circuit. The radio frequency read-write chip is connected with the control chip; the radio frequency front-end circuit is connected with the control chip and the radio frequency read-write chip; the power supply circuit comprises at least two branches, a first resistor and a first triode, input ends of the at least two branches are electrically connected, the at least two branches comprise a first branch electrically connected with the radio frequency front-end circuit and a second branch electrically connected with the control chip; wherein an enable pin of a voltage converter in the first branch is connected with an input end of the first triode, the input end of the first triode is electrically connected with an output end of the second branch through the first resistor, an output end of the first triode is grounded, and a base level of the first triode is electrically connected with a first end of the control chip. The application can reduce the power consumption of the handheld device and save the electric energy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of reader-writer technology, in particular to a handheld device. BACKGROUND

[0002] Radio frequency identification technology has the advantages of long reading and writing distance, high security, and is widely used in logistics, wine anti-counterfeiting, clothing and other industries. The function of the handheld device is to send a modulated wave signal to at least one tag, and the tag is activated by the same modulated radio frequency carrier receiving power, and the tag backscatters the signal. The radio frequency reading and writing module in the handheld device processes the backscattered signal of the tag by demodulation, amplification and decoding, etc., to realize reading of the data stored in the tag, and also can rewrite the data of the tag.

[0003] The current handheld device also has the problems of high power consumption and power waste. SUMMARY

[0004] The main purpose of the present application is to provide a handheld device to reduce the power consumption of the handheld device and save power.

[0005] To achieve the above purpose, one technical scheme adopted by the present application is to provide a handheld device, which comprises a control chip, a radio frequency reading and writing chip, a radio frequency front-end circuit and a power supply circuit.

[0006] The radio frequency reading and writing chip is connected with the control chip;

[0007] The radio frequency front-end circuit is connected with the control chip and the radio frequency reading and writing chip;

[0008] The power supply circuit comprises at least two branches, a first resistor and a first triode, the input ends of the at least two branches are electrically connected, and the at least two branches comprise a first branch electrically connected with the radio frequency front-end circuit and a second branch electrically connected with the control chip;

[0009] The enable pin of the voltage converter in the first branch is connected with the input end of the first triode, the input end of the first triode is electrically connected with the output end of the second branch through the first resistor, the output end of the first triode is grounded, and the base level of the first triode is electrically connected with the first end of the control chip.

[0010] The radio frequency front-end circuit comprises a voltage stabilizer and a power amplifier, the enable pin of the voltage stabilizer is electrically connected with the second end of the control chip, the output end of the voltage stabilizer is electrically connected with the control end of the power amplifier, the radio frequency signal output end of the radio frequency reading and writing chip is electrically connected with the input end of the power amplifier, and the output end of the power amplifier is connected with an antenna.

[0011] The radio frequency front-end circuit comprises:

[0012] The filter is electrically connected between the radio frequency signal output end of the radio frequency read-write chip and the input end of the power amplifier.

[0013] The transceiver isolation unit is connected between the output end of the power amplifier and the input end of the transceiver isolation unit, the through end of the transceiver isolation unit is connected to the antenna, the coupling end of the transceiver isolation unit is electrically connected to the first input end of the radio frequency read-write chip, and the isolation end of the transceiver isolation unit is electrically connected to the second input end of the radio frequency read-write chip.

[0014] The power detector is electrically connected between the coupling end of the transceiver isolation unit and the third end of the control chip.

[0015] The handheld device comprises a first balanced-unbalanced converter and a second balanced-unbalanced converter, the coupling end of the transceiver isolation unit is electrically connected to the first input end of the radio frequency read-write chip through the first balanced-unbalanced converter, and the isolation end of the transceiver isolation unit is electrically connected to the second input end of the radio frequency read-write chip through the second balanced-unbalanced converter.

[0016] The output end of the first branch is connected to the power supply end of the power amplifier, and the output end of the third branch of the at least two branches is connected to the input end of the voltage stabilizer.

[0017] The power supply circuit further comprises at least one sub-circuit, the input end of all the sub-circuits is connected to the output end of the third branch, the at least one sub-circuit comprises a first sub-circuit, a second sub-circuit and a third sub-circuit, the first sub-circuit is electrically connected to the power supply end and the input end of the power detector, and the second sub-circuit and the third sub-circuit are connected to the radio frequency read-write chip.

[0018] The power supply circuit further comprises a fourth resistor, a fifth resistor, a sixth resistor and a second triode.

[0019] The enable pin of the voltage stabilizer in each sub-circuit is connected to the input end of the second triode, the output end of the second branch is electrically connected to the input end of the second triode through the fourth resistor, the output end of the second branch is electrically connected to the base of the second triode through the fifth resistor and the sixth resistor, and the connection end of the fifth resistor and the sixth resistor is electrically connected to the fourth end of the control chip.

[0020] The handheld device further comprises a temperature detector, the temperature detector is powered by the third branch of the at least two branches, and the output end of the temperature detector is connected to the fifth end of the control chip.

[0021] The handheld device further comprises at least one of a serial peripheral interface, a debugging interface and a universal asynchronous receiver-transmitter interface, and the serial peripheral interface, the debugging interface and the universal asynchronous receiver-transmitter interface are electrically connected to the control chip.

[0022] The handheld device comprises a first crystal resonator and a second crystal resonator, the first crystal resonator is electrically connected with the radio frequency read-write chip, and the second crystal resonator is electrically connected with the control chip.

[0023] The first crystal resonator is a temperature compensation crystal resonator, and the first triode is an NPN triode.

[0024] The power supply circuit of the present application comprises a first branch electrically connected with the radio frequency front-end circuit and a second branch electrically connected with the control chip. The enable pin of the voltage converter in the first branch is connected with the input end of the first triode, the input end of the first triode is electrically connected with the input end of the second branch through the first resistor, the output end of the first triode is grounded, and the base level of the first triode is electrically connected with the first end of the control chip. In this way, the control chip can be started and run by supplying power to the control chip through the first branch, the switching state of the first triode can be controlled based on the control signal output by the first end of the control chip, the voltage at the input end of the first triode can be controlled when the first triode is turned on, and the change of the voltage at the input end of the first triode will cause the switching state of the voltage converter in the first branch to change. Therefore, the handheld device of the present application can control the on-off state of the first branch through the control chip, so that the first branch can be in an off state when it is not necessary to transmit and receive radio frequency signals, thereby saving power, and the voltage input to the enable pin of the voltage converter is within the voltage range that the voltage converter can withstand through the first triode, so as to protect the voltage converter. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a structural schematic diagram of an embodiment of the handheld device of the present application;

[0026] Figure 2 is a structural schematic diagram of an embodiment of the power supply circuit in the handheld device of the present application;

[0027] Figure 3 is a structural schematic diagram of an embodiment of the handheld device of the present application;

[0028] Figure 4 is a structural schematic diagram of an embodiment of the radio frequency front-end circuit in the handheld device of the present application;

[0029] Figure 5 is a schematic diagram of an embodiment of the radio frequency read-write chip in the handheld device of the present application;

[0030] Figure 6 is a schematic diagram of an embodiment of the control chip in the handheld device of the present application;

[0031] Figure 7 is a schematic diagram of an embodiment of the serial peripheral interface in the handheld device of the present application. DETAILED DESCRIPTION

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0034] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0035] Please see Figure 1 , Figure 1 This is a schematic diagram of one embodiment of the handheld device 1 of this application. The handheld device can be a handheld scanner or similar device. Figure 1 As shown, the handheld device 1 includes a control chip 13, an RF read / write chip 11, an RF front-end circuit 14, and a power supply circuit 12.

[0036] The radio frequency read / write chip 11 of this application can integrate functions such as radio frequency signal modulation and demodulation, encoding and decoding, and baseband signal spread spectrum as specified by the UHF protocol. It can also integrate phase-locked loop, voltage-controlled oscillator and / or phase detector.

[0037] The power supply circuit 12 can be electrically connected to the control chip 13, the RF read / write chip 11 and the RF front-end circuit 14 to provide the power required for the operation of the control chip 13, the RF read / write chip 11 and the RF front-end circuit 14.

[0038] like Figure 2As shown, the power supply circuit 12 may include at least two branches, a first resistor R3, and a first transistor Q1. The input terminals of all branches are electrically connected. The at least two branches include a first branch 121 and a second branch 122. The output terminal of the first branch 121 is electrically connected to the RF front-end circuit 14, and the output terminal of the second branch 122 is electrically connected to the control chip 13, so that the RF front-end circuit 14 is powered through the first branch 121, and the control chip 13 is powered through the second branch 122.

[0039] In this circuit, the enable pin of the voltage converter U1 in the first branch 121 is connected to the input terminal of the first transistor Q1. The input terminal of the first transistor Q1 is electrically connected to the output terminal of the second branch 122 through the first resistor R3. The output terminal of the first transistor Q1 is grounded, and the base of the first transistor Q1 is electrically connected to the first terminal of the control chip 13. This allows the control chip 13 to be powered by the second branch 122, enabling it to start operating. The switching state of the first transistor Q1 can then be controlled based on the control signal output from the first terminal of the control chip 13. The voltage at the input terminal of the first transistor Q1 is controlled by the control chip 13. Changes in the input voltage of the first transistor Q1 cause a change in the switching state of the voltage converter U1 in the first branch 121. Therefore, the handheld device 1 of this application can control the on / off state of the first branch 121 through the control chip 13. This allows the first branch 121 to be in an open-circuit state when radio frequency signals are not needed, saving power. Furthermore, the first transistor Q1 ensures that the voltage input to the enable pin of the voltage converter U1 is within the voltage converter U1's tolerance range, thus protecting the voltage converter U1. The first transistor Q1 can be an NPN transistor, in which case the collector of the first transistor Q1 is its input terminal, and the emitter of the first transistor Q1 is its output terminal. Alternatively, in other embodiments, the first transistor Q1 can be a PNP transistor, in which case the collector of the first transistor Q1 is its output terminal, and the emitter of the first transistor Q1 is its input terminal.

[0040] Optionally, the power supply circuit 12 may further include a second resistor R4 and a third resistor R5 connected in series. The output terminal of the second branch 122 is connected to the base of the first transistor Q1 through the second resistor R4 and the third resistor R5 connected in series. One end of the second resistor R4 and the third resistor R5 is connected to the first terminal of the control chip 13, so that the voltage divider formed by the second resistor R4 and the third resistor R5 amplifies the change of the control signal output from the first terminal of the control chip 13. When the change of the control signal output from the first terminal of the control chip 13 is small, the base voltage of the first transistor Q1 will also have a relatively large change, so as to improve the control efficiency of the control chip 13.

[0041] like Figure 3 and Figure 4 As shown, the RF front-end circuit 14 of this application may include a power amplifier 142, a voltage regulator 144, a filter 141, a transceiver isolation unit 143 and / or a power detector 145, in order to cooperate with the RF read / write chip 11 and the antenna 150 to realize the reception and transmission of RF signals.

[0042] For example, the RF front-end circuit 14 includes a power amplifier 142, a filter 141, and a transceiver isolation unit 143. The RF signal transmission process may include: the transmitted signal is first output from the RF signal output terminal of the RF read / write chip 11 to the filter 141; the filter 141 filters the transmitted signal and outputs it to the power amplifier 142; the power amplifier 142 amplifies the transmitted signal; the amplified transmitted signal is output from the transceiver isolation unit 143 to the antenna 150; and then the antenna 150 converts the transmitted signal into electromagnetic waves and radiates them into the air. The RF signal reception process may include: the antenna 150 receives the tag signal and inputs it to the input terminal of the RF read / write chip 11 via the transceiver isolation unit 143, so that the RF read / write chip 11 can decode the received signal. Specifically, the transceiver isolation unit 143 can convert the received signal into two signals: one signal is output from the isolation terminal of the transceiver isolation unit 143 to the RF read / write chip 11, and the other signal is output from the coupling terminal of the transceiver isolation unit 143 to the RF read / write chip 11. Optionally, the receiving and transmitting antennas 150 can be the same antenna 150, or different antennas 150 can be used.

[0043] The input terminal of the power amplifier 142 can be electrically connected to the RF signal output terminal of the RF read / write chip 11, and the output terminal of the power amplifier 142 is electrically connected to the antenna 150. The power amplifier 142 amplifies the RF signal output by the RF read / write chip 11 and transmits the amplified signal to the antenna 150 so that the antenna 150 can convert the RF signal into electromagnetic waves and radiate it.

[0044] The enable pin of the voltage regulator 144 is electrically connected to the second terminal of the control chip 13, and the output terminal of the voltage regulator 144 is electrically connected to the control gain terminal of the power amplifier 142. Thus, the switching state of the voltage regulator 144 can be controlled by the control chip 13, thereby controlling the working state of the power amplifier 142. This makes the voltage of the control gain of the power amplifier 142 a square wave with a certain duty cycle. The power amplifier 142 operates in a discontinuous manner, and different degrees of power consumption reduction are achieved by using different duty cycles.

[0045] Optionally, filter 141 is disposed between the RF signal output terminal of RF read / write chip 11 and power amplifier 142. This filter first filters the RF signal output by RF read / write chip 11 before outputting the filtered RF signal to power amplifier 142. This reduces out-of-band interference and signal attenuation, and also achieves impedance matching. At least one capacitor may also be disposed between filter 141 and power amplifier 142, for example... Figure 4 C21 and C22.

[0046] Additionally, a transceiver isolation unit 143 is disposed between the power amplifier 142 and the antenna 150. The transceiver isolation unit 143 isolates the transmitted and received signals and also serves as an impedance matcher. The transceiver isolation unit 143 in this application can be a circulator or a coupler, but is not limited to these. For example, the transceiver isolation unit 143 can be a coupler, with the output terminal of the power amplifier 142 connected to the input terminal of the transceiver isolation unit 143, the through terminal of the transceiver isolation unit 143 connected to the antenna 150, the coupling terminal of the transceiver isolation unit 143 electrically connected to the first input terminal of the RF read / write chip 11, and the isolation terminal of the transceiver isolation unit 143 electrically connected to the second input terminal of the RF read / write chip 11.

[0047] The coupling terminal of the transceiver isolation unit 143 can also be electrically connected to the third terminal of the control chip 13 through the power detector 145. The power detector 145 detects the power of the received signal or the transmitted signal and sends the power of the received signal or the transmitted signal to the control chip 13. The control chip 13 can determine whether the power of the received signal or the transmitted signal is within the normal range and whether the circuit is in normal working condition. It can also control the power front-end circuit based on the power of the received signal or the transmitted signal to ensure the normal operation of the handheld device 1.

[0048] Optionally, to ensure that the RF read / write chip 11 processes the received signal normally, such as Figure 5 As shown, a balanced-to-unbalanced converter can be provided between the transceiver isolation unit 143 and the RF read / write chip 11 in the RF signal receiving loop. This converter transforms the unbalanced signal output from the transceiver isolation unit 143 into a balanced signal that the RF read / write chip 11 can analyze and process, allowing the RF read / write chip 11 to receive and decode it. For example, as... Figure 5 As shown, the handheld device 1 includes a first balanced-to-unbalanced converter U14 and a second balanced-to-unbalanced converter U13. The coupling terminal of the transceiver isolation unit 143 is electrically connected to the first input terminal of the radio frequency read / write chip 11 through the first balanced-to-unbalanced converter U14, and the isolation terminal of the transceiver isolation unit 143 is electrically connected to the second input terminal of the read / write chip through the second balanced-to-unbalanced converter U13.

[0049] Furthermore, an LCR matching circuit may be provided between the first balanced-to-unbalanced converter U14 and the RF read / write chip 11 to perform level and frequency matching and low-pass filtering on the balanced signal output by the first balanced-to-unbalanced converter. The LCR matching circuit may include a first inductor L9, a second capacitor C47, and a third capacitor C48. The second capacitor C47 is connected between the first balanced-to-unbalanced converter U14 and the RF read / write chip 11, and the third capacitor C48 is also connected between them. One end of the first inductor L9 is connected to the line between the first balanced-to-unbalanced converter U14 and the second capacitor C47, and the other end is connected to the line between the first balanced-to-unbalanced converter U14 and the third capacitor C48. The smaller the capacitance values ​​of the second and third capacitors C48, the higher the frequency and the better the bandwidth, and vice versa.

[0050] Optionally, the handheld device 1 of this application may further include a first crystal resonator Y1 electrically connected to the RF read / write chip 11, so as to generate a baseband signal source through the first crystal resonator Y1, and then convert the baseband signal source into an RF transmission signal through the internal phase-locked loop of the RF read / write chip 11. The first crystal resonator Y1 may be a temperature-compensated crystal resonator.

[0051] In addition, such as Figure 6 As shown, the handheld device 1 may also include a second crystal resonator Y2 electrically connected to the control chip 13.

[0052] Please continue reading. Figure 4 The handheld device 1 may also include a temperature detector U11, which detects the internal temperature of the handheld device 1 and sends the detected temperature to the fifth terminal of the control chip 13 through its output terminal. The control chip 13 can control the operating state of the power supply circuit 12 and / or the radio frequency front-end circuit 14 based on the detected temperature to ensure the normal operation of the handheld device 1 and avoid malfunctions or burnout caused by excessive temperature. Optionally, the input terminal of the temperature detector U11 may be connected to the third branch 123 of at least two branches to power the temperature detector U11 through the third branch 123 of the power supply circuit 12. In addition, the input terminal and / or output terminal of the temperature detector U11 may also be connected to filter capacitors (C42, C43) to filter the signals input to the temperature detector U11 and / or the output signals of the temperature detector U11 through the filter capacitors (C42, C43). More specifically, the temperature detector can be used to detect the temperature of the RF front-end circuit 14. When the RF front-end temperature is too high, the duty cycle of the output signal at the second terminal of the control chip 13 is controlled to reduce the power consumption of the power amplifier 142, thereby controlling the temperature of the RF front-end circuit 14 within the suitable temperature range.

[0053] To match the various components in the handheld device 1, the power supply circuit 12 can convert an external power source (such as a lithium battery) into a power source suitable for the use of the aforementioned components, thus providing normal power to the entire system.

[0054] For details, please continue reading Figure 2 At least two branches may also include a third branch 123. The output of the third branch 123 is connected to the input of the regulator 144 in the RF front-end circuit 14.

[0055] The power supply circuit 12 may further include at least one sub-path, the input terminals of all sub-paths being connected to the output terminal of the third branch 123. The number of sub-paths is not limited. For example, at least one sub-path may include three sub-paths: a first sub-path 125, a second sub-path 124, and a third sub-path 126. The first sub-path 125 is electrically connected to the power supply terminal and the input terminal of the power detector 145. The first sub-path 125, the second sub-path 124, and the third sub-path 126 are connected to the RF read / write chip. The second sub-path 124 may also be electrically connected to the first crystal resonator Y1.

[0056] The power supply circuit 12 may also include a fourth resistor R6, a fifth resistor R7, a sixth resistor R8, and a second transistor Q2. The enable pin of the voltage regulator (U4, U5, U6) in each sub-circuit is connected to the input terminal of the second transistor Q2. The output terminal of the second branch 122 is electrically connected to the input terminal of the second transistor Q2 through the fourth resistor R6. The output terminal of the second transistor Q2 is grounded. The base of the second transistor Q2 is electrically connected to the output terminal of the second branch 122 through the series-connected fifth resistor R7 and sixth resistor R8. The connection point of the fifth resistor R7 and the sixth resistor R8 is electrically connected to the fourth terminal of the control chip 13. The switching state of the second transistor Q2 can be controlled based on the control signal output from the fourth terminal of the control chip 13, and the second transistor Q2 is switched on when it is turned on. The voltage at the input terminal of the second transistor Q2 is controlled, and changes in the input voltage of the second transistor Q2 will change the switching state of the voltage regulators (U4, U5, U6) in the sub-circuit. Therefore, the handheld device 1 of this application can control the on / off state of the sub-circuit through the control chip 13. This allows the first branch 121 and all sub-circuits to be in an open-circuit state when no radio frequency signal transmission or reception is required, saving power. Furthermore, the second transistor Q2 ensures that the voltage input to the enable pin of the voltage regulators (U4, U5, U6) is within the voltage regulators' (U4, U5, U6) tolerance range, thus protecting the voltage regulators (U4, U5, U6). Additionally, the control chip 13 can make the voltage of each sub-circuit a square wave with a certain duty cycle, achieving different levels of power consumption reduction through different duty cycles. Similarly, the second transistor Q2 can also be an NPN transistor or a PNP transistor.

[0057] Optionally, such asFigure 6 and Figure 7 As shown, the handheld device 1 also includes at least one of a serial peripheral interface J1, a debug interface J2, and a universal asynchronous receiver / transmitter (UART) interface J3. The serial peripheral interface J1, the debug interface J2, and the UART interface J3 are all electrically connected to the control chip 13.

[0058] Additionally, test points can be provided on the power supply circuit 12 to facilitate testing. For example, such as... Figure 2 As shown, assume that the power supply circuit 12 includes 3 branches and 3 sub-circuits, and each branch output terminal and each sub-circuit output terminal has a test point, for a total of 6 test points.

[0059] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A handheld device, characterized in that, The handheld device includes: Control chip; An RF read / write chip is connected to the control chip; The radio frequency front-end circuit is connected to the control chip and the radio frequency read / write chip; A power supply circuit, comprising at least two branches, a first resistor and a first transistor, wherein the input terminals of the at least two branches are electrically connected, and the at least two branches include a first branch electrically connected to the radio frequency front-end circuit and a second branch electrically connected to the control chip; In this circuit, the enable pin of the voltage converter in the first branch is connected to the input terminal of the first transistor. A change in the input voltage of the first transistor will cause a change in the switching state of the voltage converter in the first branch. The input terminal of the first transistor is electrically connected to the output terminal of the second branch through the first resistor. The output terminal of the first transistor is grounded. The base of the first transistor is electrically connected to the first terminal of the control chip. The radio frequency front-end circuit includes a voltage regulator, and the enable pin of the voltage regulator is electrically connected to the second terminal of the control chip. The handheld device also includes a temperature detector, the output of which is connected to the fifth terminal of the control chip.

2. The handheld device according to claim 1, characterized in that, The radio frequency front-end circuit includes a power amplifier. The output terminal of the voltage regulator is electrically connected to the control terminal of the power amplifier. The radio frequency signal output terminal of the radio frequency read / write chip is electrically connected to the input terminal of the power amplifier. The output terminal of the power amplifier is connected to the antenna.

3. The handheld device according to claim 2, characterized in that, The radio frequency front-end circuit includes: The radio frequency signal output terminal of the radio frequency read / write chip is electrically connected to the input terminal of the power amplifier through the filter, and the input terminal of the filter is connected to the output terminal of the filter through a first capacitor. The transceiver isolation unit has its output terminal connected to the input terminal of the power amplifier, its through terminal connected to the antenna, its coupling terminal electrically connected to the first input terminal of the RF read / write chip, and its isolation terminal electrically connected to the second input terminal of the RF read / write chip. A power detector is provided, and the coupling terminal of the transceiver isolation unit is electrically connected to the third terminal of the control chip through the power detector.

4. The handheld device according to claim 3, characterized in that, The handheld device includes a first balanced-to-unbalanced converter and a second balanced-to-unbalanced converter. The coupling terminal of the transceiver isolation unit is electrically connected to the first input terminal of the RF read / write chip through the first balanced-to-unbalanced converter, and the isolation terminal of the transceiver isolation unit is electrically connected to the second input terminal of the RF read / write chip through the second balanced-to-unbalanced converter.

5. The handheld device according to claim 3, characterized in that, The output terminal of the first branch is connected to the power supply terminal of the power amplifier; the output terminal of the third branch of the at least two branches is connected to the input terminal of the voltage regulator. The power supply circuit further includes at least one sub-path, the input terminals of all sub-paths are connected to the output terminal of the third branch, the at least one sub-path includes a first sub-path, a second sub-path and a third sub-path, the first sub-path is electrically connected to the power supply terminal and the input terminal of the power detector, and the second sub-path and the third sub-path are connected to the radio frequency read / write chip.

6. The handheld device according to claim 5, characterized in that, The power supply circuit also includes a fourth resistor, a fifth resistor, a sixth resistor, and a second transistor; The enable pin of the regulator in each sub-circuit is connected to the input terminal of the second transistor. The output terminal of the second branch is electrically connected to the input terminal of the second transistor through the fourth resistor. The output terminal of the second branch is electrically connected to the base of the second transistor through the fifth and sixth resistors. The connection terminals of the fifth and sixth resistors are electrically connected to the fourth terminal of the control chip.

7. The handheld device according to claim 1, characterized in that, The temperature detector is powered by the third branch of the at least two branches.

8. The handheld device according to claim 1, characterized in that, The handheld device further includes at least one of a serial peripheral interface, a debugging interface, and a universal asynchronous transceiver interface, wherein the serial peripheral interface, the debugging interface, and the universal asynchronous transceiver interface are all electrically connected to the control chip.

9. The handheld device according to claim 1, characterized in that, The handheld device includes a first crystal resonator and a second crystal resonator. The first crystal resonator is electrically connected to the radio frequency read / write chip, and the second crystal resonator is electrically connected to the control chip.

10. The handheld device according to claim 9, characterized in that, The first crystal resonator is a temperature-compensated crystal resonator, and the first transistor is an NPN transistor.

Images