CN114553168A - Filter circuit - Google Patents

Filter circuit Download PDF

Info

Publication number
CN114553168A
CN114553168A CN202011576142.4A CN202011576142A CN114553168A CN 114553168 A CN114553168 A CN 114553168A CN 202011576142 A CN202011576142 A CN 202011576142A CN 114553168 A CN114553168 A CN 114553168A
Authority
CN
China
Prior art keywords
resistor
switch
coupled
terminal
operational amplifier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202011576142.4A
Other languages
Chinese (zh)
Inventor
刘宇华
李彦锋
王智利
林镇杰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Airoha Technology Corp
Original Assignee
Airoha Technology Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Airoha Technology Corp filed Critical Airoha Technology Corp
Publication of CN114553168A publication Critical patent/CN114553168A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/06—Frequency selective two-port networks including resistors
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/38—Impedance-matching networks
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Landscapes

  • Networks Using Active Elements (AREA)

Abstract

The invention provides a filter circuit. The filter circuit comprises a first filter module, a second filter module and a third filter module. The first filtering module and the second filtering module respectively comprise an operational amplifier, a plurality of resistors, a plurality of capacitors and a plurality of switches. The filter circuit can be switched between a first mode and a second mode by the combination of conduction and non-conduction of the switches. The first mode is a narrow band mode, and the filter circuit has a narrower filter bandwidth. The second mode is a wide frequency mode, and the filter circuit has a wider filter bandwidth.

Description

Filter circuit
Technical Field
The present invention relates to a filter circuit, and more particularly, to a filter circuit for a multiband receiver.
Background
The filter circuit is one of the important circuits constituting the receiver. Generally, the filter circuit is designed according to the frequency band to be received by the receiver. The frequency bands used by different countries or systems vary, and common frequency bands include narrow band (2.7MHz), wide band (15MHz), and ultra wide band (27MHz), for example. As receivers are required to receive more and more frequency bands, the filter circuit must be improved accordingly. How to increase the receiving frequency band while simultaneously achieving low noise and low power consumption is an important goal of research and development.
Disclosure of Invention
The embodiment of the invention provides a filter circuit, which comprises a first filter module and a second filter module. The first filtering module is used for receiving a first input signal and a second input signal and comprises a first operational amplifier, a first switch and a second switch. The second filtering module is coupled to the first filtering module and includes a second operational amplifier, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch and an eighth switch. The filter circuit has a first mode and a second mode. In the first mode, by turning off the first switch, the second switch, the third switch and the fourth switch and turning on the fifth switch, the sixth switch, the seventh switch and the eighth switch, a positive output end and a negative output end of the second operational amplifier are respectively coupled to an inverting input end and a non-inverting input end of the first operational amplifier, and a sum of first order of the first filtering module and the second filtering module is a first order. In the second mode, by turning on the first switch, the second switch, the third switch and the fourth switch and turning off the fifth switch, the sixth switch, the seventh switch and the eighth switch, the positive output end and the negative output end of the second operational amplifier are not coupled to the first operational amplifier, and the sum of the orders of the first filtering module and the second filtering module is a second order which is greater than the first order.
Another embodiment of the present invention provides a filter circuit, which includes a first filter module and a second filter module. The first filtering module comprises a first operational amplifier, a first switch and a second switch. The second filtering module is coupled to the first filtering module, and includes a second operational amplifier, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, and an eighth switch, and is configured to output a first output signal and a second output signal. In the first mode, by non-conduction of the first switch, the second switch, the third switch and the fourth switch and conduction of the fifth switch, the sixth switch, the seventh switch and the eighth switch, a positive output end and a negative output end of the second operational amplifier are respectively coupled to an inverting input end and a non-inverting input end of the first operational amplifier, and the sum of the first order of the first filtering module and the first order of the second filtering module is a first order. In the second mode, by turning on the first switch, the second switch, the third switch and the fourth switch and turning off the fifth switch, the sixth switch, the seventh switch and the eighth switch, the positive output end and the negative output end of the second operational amplifier are not coupled to the first operational amplifier, and the sum of the orders of the first filtering module and the second filtering module is a second order which is greater than the first order.
The invention is described in detail below with reference to the drawings and specific examples, but the invention is not limited thereto.
Drawings
Fig. 1 is a block diagram of a filter circuit according to an embodiment of the invention.
Fig. 2 is a block diagram of a filter circuit according to another embodiment of the invention.
The circuit of fig. 3A illustrates a circuit architecture of the filtering circuit of fig. 1 operating in a first mode.
The circuit diagram of fig. 3B illustrates a circuit architecture for the filtering circuit of fig. 1 operating in a second mode.
Wherein, the reference numbers:
10. 20: filter circuit
102: first filtering module
104: second filter module
106: third filtering module
OPA1 to OPA 3: operational amplifier
R1 to R12: resistor with a resistor element
C1 to C7: capacitor with a capacitor element
S1-S8: switch with a switch body
S-in 1: first input signal
S-in 2: second input signal
S-out 1: first output signal
S-out 2: second output signal
Detailed Description
The invention will be described in detail with reference to the following drawings, which are provided for illustration purposes and the like:
fig. 1 is a block diagram of a filter circuit 10 according to an embodiment of the invention. Referring to fig. 1, the filter circuit 10 includes a first filter module 102, a second filter module 104, and a third filter module 106.
The first filtering module 102 includes an operational amplifier OPA1, a plurality of resistors R1 and R2, a plurality of capacitors C1 and C2, and a plurality of switches S1 and S2.
In the first filtering module 102, an inverting input terminal of the operational amplifier OPA1 is configured to receive a first input signal S-in 1. A non-inverting input of the operational amplifier OPA1 receives a second input signal S-in 2. A first terminal of the resistor R1 is coupled to the inverting input of the operational amplifier OPA 1. A second terminal of the resistor R1 is coupled to a first terminal of the switch S1. A first terminal of the capacitor C1 is coupled to the inverting input of the operational amplifier OPA 1. A second terminal of the capacitor C1 is coupled to a second terminal of the switch S1 and a positive output terminal of the operational amplifier OPA 1. A first terminal of the resistor R2 is coupled to the non-inverting input of the operational amplifier OPA 1. A second terminal of the resistor R2 is coupled to a first terminal of the switch S2. A first terminal of the capacitor C2 is coupled to the non-inverting input of the operational amplifier OPA 1. A second terminal of the capacitor C2 is coupled to a second terminal of the switch S2 and a negative output terminal of the operational amplifier OPA 1.
The second filtering module 104 includes an operational amplifier OPA2, a plurality of resistors R3, R4, R5, R6, R7, and R8, a plurality of capacitors C3, C4, and C5, and a plurality of switches S3, S4, S5, S6, S7, and S8.
In the second filtering module 104, a first terminal of the resistor R3 is coupled to the negative output terminal of the operational amplifier OPA 1. A first terminal of the resistor R4 is coupled to the positive output terminal of the operational amplifier OPA 1. A first terminal of the capacitor C3 is coupled to a first terminal of the switch S3. A second terminal of the switch S3 is coupled to a second terminal of the resistor R3. A second terminal of the capacitor C3 is coupled to a first terminal of the switch S4. A second terminal of the switch S4 is coupled to a second terminal of the resistor R4. A first end of the resistor R5 is coupled to the second end of the resistor R3. A first terminal of the resistor R7 is coupled to a first terminal of the switch S5. A second terminal of the resistor R7 is coupled to a first terminal of the switch S7 and a positive output terminal of the operational amplifier OPA 2. A second terminal of the switch S7 is coupled to the second terminal of the resistor R1. A first terminal of the capacitor C4 is coupled to a second terminal of the switch S5. A second terminal of the capacitor C4 is coupled to the positive output terminal of the operational amplifier OPA 2. The second terminal of the switch S5 is coupled to a second terminal of the resistor R5 and an inverting input terminal of the operational amplifier OPA 2. A first end of the resistor R6 is coupled to the second end of the resistor R4. A first terminal of the resistor R8 is coupled to a first terminal of the switch S6. A second terminal of the resistor R8 is coupled to a first terminal of the switch S8 and a negative output terminal of the operational amplifier OPA 2. A second terminal of the switch S8 is coupled to the second terminal of the resistor R2. A first terminal of the capacitor C5 is coupled to a second terminal of the switch S6. A second terminal of the capacitor C5 is coupled to the negative output terminal of the operational amplifier OPA 2. The second terminal of the switch S6 is coupled to a second terminal of the resistor R6 and a non-inverting input of the operational amplifier OPA 2.
The third filtering module 106 includes an operational amplifier OPA3, a plurality of resistors R9, R10, R11 and R12, and a plurality of capacitors C6 and C7.
In the third filtering module 106, a first terminal of the resistor R9 is coupled to the negative output terminal of the operational amplifier OPA 2. A first terminal of the resistor R11 is coupled to a second terminal of the resistor R9 and an inverting input of the operational amplifier OPA 3. A second terminal of the resistor R11 is coupled to a positive output terminal of the operational amplifier OPA 3. A first terminal of the capacitor C6 is coupled to the inverting input of the operational amplifier OPA 3. A second terminal of the capacitor C6 is coupled to the positive output terminal of the operational amplifier OPA 3. A first terminal of the resistor R10 is coupled to the positive output terminal of the operational amplifier OPA 2. A first terminal of the resistor R12 is coupled to a second terminal of the resistor R10 and a non-inverting input of the operational amplifier OPA 3. A second terminal of the resistor R12 is coupled to a negative output terminal of the operational amplifier OPA 3. A first terminal of the capacitor C7 is coupled to the non-inverting input of the operational amplifier OPA 3. A second terminal of the capacitor C7 is coupled to the negative output terminal of the operational amplifier OPA 3. The positive output terminal of the operational amplifier OPA3 is used for outputting a first output signal S-out 1. The negative output terminal of the operational amplifier OPA3 is used for outputting a second output signal S-out 2.
In one embodiment, the resistors R1 and R2 have the same resistance value as each other. The resistors R3 and R4 have the same resistance value. The resistors R5 and R6 have the same resistance value. The resistors R7 and R8 have the same resistance value. The resistors R9 and R10 have the same resistance value. The resistors R11 and R12 have the same resistance value. The capacitance values of the capacitors C1 and C2 are the same. The capacitance values of the capacitors C4 and C5 are the same. The capacitance values of the capacitors C6 and C7 are the same.
The filter circuit 10 has a first mode and a second mode. Switching between the first mode and the second mode can be achieved by changing the combination of conduction and non-conduction of the switches S1-S8, which is described in detail in the embodiment of fig. 3A and 3B. In one embodiment, the switches S1-S8 may be controlled by a control unit (not shown). The control unit can send control signals to the switches S1 to S8 according to a mode switching command issued by the user to control the switches S1 to S8 to be turned on or turned off respectively.
The circuit diagram of fig. 3A illustrates the circuit architecture of the filter circuit 10 of fig. 1 operating in a first mode. Referring to fig. 3A, when the switches S1 to S4 are not turned on and the switches S5 to S8 are turned on, the filter circuit 10 is switched to the first mode. In this embodiment, the first mode is a narrowband mode. In the first mode, the positive output terminal and the negative output terminal of the operational amplifier OPA2 of the second filter module 104 are coupled to the inverting input terminal and the non-inverting input terminal of the first filter module 102 through the resistor R1 and the resistor R2, respectively. Further, a resistor R7 and a capacitor C4 are connected in parallel between the inverting input and the positive output of the operational amplifier OPA2, and similarly, a resistor R8 and a capacitor C5 are connected in parallel between the non-inverting input and the negative output of the operational amplifier OPA 2. In response to the non-conduction of the switches S3 and S4, the capacitor C3 is not electrically connected to other electronic components of the second filtering module 104, and thus the capacitor C3 does not participate in the filtering operation of the first input signal S-in1 and the second input signal S-in 2.
The sum of the orders (orders) contributed by the first filtering module 102 and the second filtering module 104 is a first order, which is two orders in this embodiment. In some embodiments, the equivalent circuit of the combination of the first filtering module 102 and the second filtering module 104 in the first mode may be equivalent to a Tow-Thomas second order filter. The third filtering module 106 contributes to a second order. Accordingly, the filter circuit 10 operating in the first mode can be equivalent to a fourth order filter.
The circuit diagram of fig. 3B illustrates the circuit architecture of the filtering circuit 10 of fig. 1 operating in a second mode. Referring to fig. 3B, when the switches S1 through S4 are turned on and the switches S5 through S8 are turned off, the filter circuit 10 is switched to the second mode. In this embodiment, the second mode is a broadband mode. In the second mode, the positive and negative outputs of the OPA2 of the second filtering module 104 are not fed back to the inverting and non-inverting inputs of the first filtering module 102. Accordingly, the sum of the orders contributed by the first filtering module 102 and the second filtering module 104 is a second order greater than the first order, and the second order is three orders in the embodiment. In some embodiments, the first filtering module 102 in the second mode contributes a first order filtering effect, and the second filtering module 104 in the second mode may be equivalent to a second order multi-feedback filter. The third filtering module 106 contributes to a second order. Accordingly, the filter circuit 10 operating in the second mode can be equivalent to a fifth order filter.
Generally, the order of the filter is positively correlated to the bandwidth of the signal output by the filter. Therefore, the bandwidth of the filter circuit 10 of the fourth order in the first mode is narrower than that of the filter circuit 10 of the fifth order in the second mode. Also, generally, the bandwidth of the filter circuit is positively correlated to the number of frequency bands that can be filtered. Therefore, the number of frequency bands that can be filtered by the filter circuit 10 in the first mode is less than that in the second mode. For example, in one embodiment, the filter circuit 10 may filter signals in two frequency bands of a narrow frequency (2MHz (mega hertz)) and a wide frequency (15MHz), or may filter signals in two frequency bands of a wide frequency (15MHz) and an ultra wide frequency (27MHz) in the first mode. On the other hand, the filter circuit 10 can filter signals of three frequency bands including a narrow band (2MHz), a wide band (15MHz), and an ultra wide band (27MHz) in the second mode. That is, the filter circuit 10 can adjust the sum of the orders contributed by the first filter module 102 and the second filter module 104 by adjusting the combinations of the switches S1 to S8, so as to change the bandwidth of the filter circuit 10.
Generally, the total number of minimum requirements of the operational amplifiers constituting the high-order filter circuit is larger than that of the low-order filter circuit, which results in the power consumption of the high-order filter circuit being larger than that of the low-order filter circuit, and thus the high-order filter circuit is relatively unsuitable for low-power applications.
To meet the requirements of low power applications, the total number of operational amplifiers of the filter circuit is at least minimized. In the present invention, the total amount of operational amplifiers of the filter circuit 10 of the present invention remains the same as the total amount of operational amplifiers in the low frequency mode even in the wide frequency mode. In other words, the filter circuit 10 of the present invention does not use more operational amplifiers than in the narrowband mode due to operation in the wideband mode. The filter circuit 10 of the present invention reconfigures the filter circuit 10, which originally provides the function of a low-order filter, by means of the switches S1 to S8, so that the configured filter circuit 10 can provide the function of a high-order filter. Therefore, the efficiency of the power consumption of the filter circuit 10 of the present invention is relatively good.
In one embodiment, the third filtering module 106 may be a programmable-gain amplifier (PGA). In this embodiment, the resistors R9, R10, R11 and R12 are variable resistors, and the ratio of the resistance of the resistor R9 to the resistance of the resistor R11 determines a gain. The resistance value of the resistor R9 is the same as that of the resistor R10, and the resistance value of the resistor R11 is the same as that of the resistor R12, so that the gain is also determined by the ratio of the resistance value of the resistor R10 to that of the resistor R12.
In another embodiment, resistors R9, R10, R11, and R12 are variable resistors and capacitors C6 and C7 are variable capacitors. The resistance values of the resistors R9 to R12 and the capacitance values of the capacitors C6 to C7 can be controlled by the control unit, and the control unit can adjust the resistance values of the resistors R9 to R12 and the capacitance values of the capacitors C6 to C7 according to whether the mode of the filter circuit 10 is the first mode or the second mode, so as to optimize the filtering effect of the filter circuit 10.
Fig. 2 is a block diagram of a filter circuit 20 according to another embodiment of the present invention. Referring to fig. 2, the filter circuit 20 is implemented by moving the third filter module 106 of fig. 1 to the front of the second filter module 104. In other words, the third filtering module 106 is an input stage of the filtering circuit 20. Accordingly, the second filtering module 104 is adapted to be an output stage of the filtering circuit 20, and the first filtering module 102 is coupled between the third filtering module 106 and the second filtering module 104 of the filtering circuit 20 as an intermediate stage of the filtering circuit 20.
For the sake of brevity, only the differences in the connections will be described below. Referring to fig. 2, the second terminal of the resistor R11, the second terminal of the capacitor C6, and the positive output terminal of the operational amplifier OPA3 are coupled to the first terminal of the resistor R2, the first terminal of the capacitor C2, and the non-inverting input terminal of the operational amplifier OPA1 of the first filtering module 102. Similarly, the second terminal of the resistor R12, the second terminal of the capacitor C7, and the negative output terminal of the operational amplifier OPA3 are coupled to the first terminal of the resistor R1, the first terminal of the capacitor C1, and the inverting input terminal of the operational amplifier OPA1 of the first filtering module 102. In addition, the positive output terminal of the operational amplifier OPA2 is used for outputting a first output signal S-out 1. The negative output terminal of the operational amplifier OPA2 is used for outputting a second output signal S-out 2.
It should be noted that the resistance values of the resistors and the capacitance values of the capacitors in the first filtering module 102 and the second filtering module 104 can be designed according to actual requirements, and the invention is not limited thereto.
The filter circuit provided by the invention has two different modes, namely a first mode and a second mode. The fourth order in the first mode is smaller than the fifth order in the second mode in the order of the filter circuit. The bandwidth of the filter circuit in the first mode is narrower than the bandwidth of the filter circuit in the second mode. The combination of the on state and the off state of the switch in the filter circuit is adjusted to adjust the sum of the orders contributed by the first filter module and the second filter module to switch between the first mode and the second mode, so as to change the bandwidth of the filter circuit. Therefore, the efficiency of the power consumption of the filter circuit of the invention is relatively better.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (12)

1. A filter circuit, comprising:
the first filtering module is used for receiving a first input signal and a second input signal and comprises a first operational amplifier, a first switch and a second switch; and
a second filtering module coupled to the first filtering module and including a second operational amplifier, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch and an eighth switch,
wherein the filter circuit has a first mode and a second mode,
wherein, in the first mode, by the non-conduction of the first switch, the second switch, the third switch and the fourth switch and the conduction of the fifth switch, the sixth switch, the seventh switch and the eighth switch, a positive output end and a negative output end of the second operational amplifier are respectively coupled to an inverting input end and a non-inverting input end of the first operational amplifier, and the sum of the first order of the first filtering module and the second filtering module is a first order, and
in the second mode, the positive output end and the negative output end of the second operational amplifier are not coupled to the first operational amplifier by the conduction of the first switch, the second switch, the third switch and the fourth switch and the non-conduction of the fifth switch, the sixth switch, the seventh switch and the eighth switch, and the sum of the orders of the first filtering module and the second filtering module is a second order which is greater than the first order.
2. The filter circuit of claim 1, further comprising:
a third filtering module coupled to the second filtering module for outputting a first output signal and a second output signal.
3. The filter circuit of claim 2,
the first filtering module further includes a first resistor, a second resistor, a first capacitor and a second capacitor,
wherein the inverting input terminal of the first operational amplifier is configured to receive the first input signal, the non-inverting input terminal of the first operational amplifier is configured to receive the second input signal, a first end of the first resistor is coupled to the inverting input terminal of the first operational amplifier, a second end of the first resistor is coupled to a first end of the first switch, a first end of the first capacitor is coupled to the inverting input terminal of the first operational amplifier, a second end of the first capacitor is coupled to a second end of the first switch and a positive output terminal of the first operational amplifier, a first end of the second resistor is coupled to the non-inverting input terminal of the first operational amplifier, a second end of the second resistor is coupled to a first end of the second switch, a first end of the second capacitor is coupled to the non-inverting input terminal of the first operational amplifier, a second terminal of the second capacitor is coupled to a second terminal of the second switch and a negative output terminal of the first operational amplifier, an
Wherein the second filter module further comprises a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a third capacitor, a fourth capacitor and a fifth capacitor,
wherein a first end of the third resistor is coupled to the negative output terminal of the first operational amplifier, a first end of the fourth resistor is coupled to the positive output terminal of the first operational amplifier, a first end of the third capacitor is coupled to a first end of the third switch, a second end of the third switch is coupled to a second end of the third resistor, a second end of the third capacitor is coupled to a first end of the fourth switch, a second end of the fourth switch is coupled to a second end of the fourth resistor, a first end of the fifth resistor is coupled to the second end of the third resistor, a first end of the seventh resistor is coupled to a first end of the fifth switch, a second end of the seventh resistor is coupled to a first end of the seventh switch and the positive output terminal of the second operational amplifier, a second end of the seventh switch is coupled to the second end of the first resistor, a first terminal of the fourth capacitor is coupled to a second terminal of the fifth switch, a second terminal of the fourth capacitor is coupled to the positive output terminal of the second operational amplifier, the second terminal of the fifth switch is coupled to a second terminal of the fifth resistor and an inverting input terminal of the second operational amplifier, a first terminal of the sixth resistor is coupled to the second terminal of the fourth resistor, a first terminal of the eighth resistor is coupled to a first terminal of the sixth switch, a second terminal of the eighth resistor is coupled to a first terminal of the eighth switch and the negative output terminal of the second operational amplifier, a second terminal of the eighth switch is coupled to the second terminal of the second resistor, a first terminal of the fifth capacitor is coupled to a second terminal of the sixth switch, a second terminal of the fifth capacitor is coupled to the negative output terminal of the second operational amplifier, the second terminal of the sixth switch is coupled to a second terminal of the sixth resistor and a non-inverting input terminal of the second operational amplifier.
4. A filter circuit as claimed in claim 3, wherein:
the third filtering module includes a third operational amplifier, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a sixth capacitor and a seventh capacitor,
wherein a first end of the ninth resistor is coupled to the negative output terminal of the second operational amplifier, a first end of the eleventh resistor is coupled to a second end of the ninth resistor and an inverting input terminal of the third operational amplifier, a second end of the eleventh resistor is coupled to a positive output terminal of the third operational amplifier, a first end of the sixth capacitor is coupled to the inverting input terminal of the third operational amplifier, a second end of the sixth capacitor is coupled to the positive output terminal of the third operational amplifier, a first end of the tenth resistor is coupled to the positive output terminal of the second operational amplifier, a first end of the twelfth resistor is coupled to a second end of the tenth resistor and a non-inverting input terminal of the third operational amplifier, a second end of the twelfth resistor is coupled to a negative output terminal of the third operational amplifier, a first terminal of the seventh capacitor is coupled to the non-inverting input terminal of the third operational amplifier, a second terminal of the seventh capacitor is coupled to the negative output terminal of the third operational amplifier, the positive output terminal of the third operational amplifier is used for outputting the first output signal, and the negative output terminal of the third operational amplifier is used for outputting the second output signal.
5. The filter circuit according to claim 4, wherein the ninth resistor, the tenth resistor, the eleventh resistor and the twelfth resistor are variable resistors, the sixth capacitor and the seventh capacitor are variable capacitors, and resistance values of the ninth resistor, the tenth resistor, the eleventh resistor and the twelfth resistor and capacitance values of the sixth capacitor and the seventh capacitor are determined according to whether a mode of the filter circuit is the first mode or the second mode.
6. The filter circuit of claim 4, wherein the ninth resistor and the eleventh resistor are variable resistors, and a gain of the third filter module is determined according to a resistance of the ninth resistor and a resistance of the eleventh resistor.
7. A filter circuit, comprising:
a first filtering module including a first operational amplifier, a first switch and a second switch; and
a second filtering module, coupled to the first filtering module, including a second operational amplifier, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch and an eighth switch, for outputting a first output signal and a second output signal;
wherein, in a first mode, by the non-conduction of the first switch, the second switch, the third switch and the fourth switch and the conduction of the fifth switch, the sixth switch, the seventh switch and the eighth switch, a positive output end and a negative output end of the second operational amplifier are respectively coupled to an inverting input end and a non-inverting input end of the first operational amplifier, and the sum of the first order of the first filtering module and the second order of the second filtering module is a first order, and
in a second mode, by turning on the first switch, the second switch, the third switch and the fourth switch and turning off the fifth switch, the sixth switch, the seventh switch and the eighth switch, the positive output end and the negative output end of the second operational amplifier are not coupled to the first operational amplifier, and the sum of the orders of the first filtering module and the second filtering module is a second order greater than the first order.
8. The filter circuit of claim 7, further comprising:
the third filtering module is coupled to the first filtering module and is used for receiving a first input signal and a second input signal.
9. The filter circuit of claim 8, wherein:
the first filtering module further includes a first resistor, a second resistor, a first capacitor and a second capacitor,
wherein a first end of the first resistor is coupled to the inverting input terminal of the first operational amplifier, a second end of the first resistor is coupled to a first end of the first switch, a first end of the first capacitor is coupled to the inverting input terminal of the first operational amplifier, a second end of the first capacitor is coupled to a second end of the first switch and a positive output terminal of the first operational amplifier, a first end of the second resistor is coupled to the non-inverting input terminal of the first operational amplifier, a second end of the second resistor is coupled to a first end of the second switch, a first end of the second capacitor is coupled to the non-inverting input terminal of the first operational amplifier, a second end of the second capacitor is coupled to a second end of the second switch and a negative output terminal of the first operational amplifier; and
the second filter module further includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a third capacitor, a fourth capacitor and a fifth capacitor,
wherein a first end of the third resistor is coupled to the negative output terminal of the first operational amplifier, a first end of the fourth resistor is coupled to the positive output terminal of the first operational amplifier, a first end of the third capacitor is coupled to a first end of the third switch, a second end of the third switch is coupled to a second end of the third resistor, a second end of the third capacitor is coupled to a first end of the fourth switch, a second end of the fourth switch is coupled to a second end of the fourth resistor, a first end of the fifth resistor is coupled to the second end of the third resistor, a first end of the seventh resistor is coupled to a first end of the fifth switch, a second end of the seventh resistor is coupled to a first end of the seventh switch and the positive output terminal of the second operational amplifier, a second end of the seventh switch is coupled to the second end of the first resistor, a first terminal of the fourth capacitor is coupled to a second terminal of the fifth switch, a second terminal of the fourth capacitor is coupled to the positive output terminal of the second operational amplifier, the second terminal of the fifth switch is coupled to a second terminal of the fifth resistor and an inverting input terminal of the second operational amplifier, a first terminal of the sixth resistor is coupled to the second terminal of the fourth resistor, a first terminal of the eighth resistor is coupled to a first terminal of the sixth switch, a second terminal of the eighth resistor is coupled to a first terminal of the eighth switch and the negative output terminal of the second operational amplifier, a second terminal of the eighth switch is coupled to the second terminal of the second resistor, a first terminal of the fifth capacitor is coupled to a second terminal of the sixth switch, a second terminal of the fifth capacitor is coupled to the negative output terminal of the second operational amplifier, the second terminal of the sixth switch is coupled to a second terminal of the sixth resistor and a non-inverting input terminal of the second operational amplifier, the positive output terminal of the second operational amplifier is used for outputting the first output signal, and the negative output terminal of the second operational amplifier is used for outputting the second output signal.
10. The filter circuit of claim 9, wherein:
the third filtering module includes a third operational amplifier, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a sixth capacitor and a seventh capacitor, wherein a first end of the ninth resistor is used for receiving the first input signal, a first end of the eleventh resistor is coupled to a second end of the ninth resistor and an inverting input terminal of the third operational amplifier, a second end of the eleventh resistor is coupled to a positive output terminal of the third operational amplifier, a first end of the sixth capacitor is coupled to the inverting input terminal of the third operational amplifier, a second end of the sixth capacitor is coupled to the positive output terminal of the third operational amplifier, a first end of the tenth resistor is used for receiving the second input signal, a first end of the twelfth resistor is coupled to a second end of the tenth resistor and a non-inverting input terminal of the third operational amplifier, a second end of the twelfth resistor is coupled to a negative output end of the third operational amplifier, a first end of the seventh capacitor is coupled to the non-inverting input end of the third operational amplifier, a second end of the seventh capacitor is coupled to the negative output end of the third operational amplifier, the positive output end of the third operational amplifier is coupled to the non-inverting input end of the first operational amplifier, and the negative output end of the third operational amplifier is coupled to the inverting input end of the first operational amplifier.
11. The filter circuit of claim 10, wherein the ninth resistor, the tenth resistor, the eleventh resistor and the twelfth resistor are variable resistors, the sixth capacitor and the seventh capacitor are variable capacitors, and resistance values of the ninth resistor, the tenth resistor, the eleventh resistor and the twelfth resistor and capacitance values of the sixth capacitor and the seventh capacitor are determined according to whether a mode of the filter circuit is the first mode or the second mode.
12. The filter circuit of claim 10, wherein the ninth resistor and the eleventh resistor are variable resistors, and a gain of the third filter module is determined according to a resistance of the ninth resistor and a resistance of the eleventh resistor.
CN202011576142.4A 2020-11-27 2020-12-28 Filter circuit Pending CN114553168A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
TW109141774 2020-11-27
TW109141774A TWI738575B (en) 2020-11-27 2020-11-27 Filter circuit

Publications (1)

Publication Number Publication Date
CN114553168A true CN114553168A (en) 2022-05-27

Family

ID=78777898

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011576142.4A Pending CN114553168A (en) 2020-11-27 2020-12-28 Filter circuit

Country Status (2)

Country Link
CN (1) CN114553168A (en)
TW (1) TWI738575B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115425998A (en) * 2022-11-08 2022-12-02 长沙驰芯半导体科技有限公司 Multi-order multi-band anti-interference intelligent ultra-wideband antenna self-adaptation method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI783808B (en) * 2021-12-02 2022-11-11 瑞昱半導體股份有限公司 Signal receiving apparatus and programmable gain amplifier having mode-switching mechanism

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5168461A (en) * 1989-08-21 1992-12-01 Industrial Technology Research Institute Switched capacitor differentiators and switched capacitor differentiator-based filters
US5391999A (en) * 1993-12-02 1995-02-21 Motorola Inc. Glitchless switched-capacitor biquad low pass filter
TW427053B (en) * 1999-03-10 2001-03-21 Nat Science Council Low voltage switched capacitor integrator having offset voltage compensation and the filter using the same
EP1891733A1 (en) * 2005-06-10 2008-02-27 Telefonaktiebolaget LM Ericsson (publ) A phase shifter device
US8260212B2 (en) * 2009-05-19 2012-09-04 Broadcom Corporation Method and system for a reconfigurable filter that is utilized by a RF transmitter and a RF receiver which are integrated on a single substrate
JP5270488B2 (en) * 2009-08-03 2013-08-21 ルネサスエレクトロニクス株式会社 Filter circuit and receiving circuit using the same
JP5846840B2 (en) * 2011-10-14 2016-01-20 ルネサスエレクトロニクス株式会社 Filter circuit and receiver
US9912311B2 (en) * 2015-07-22 2018-03-06 Samsung Electronics Co., Ltd Multimode reconfigurable amplifier and analog filter including the same
CN106849988B (en) * 2017-03-27 2022-04-12 辽宁工程技术大学 UHF-RFID reader-writer channel selection filter supporting double protocols
US10608601B2 (en) * 2017-05-31 2020-03-31 Qualcomm Incorporated Active biquad filter with oscillator circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115425998A (en) * 2022-11-08 2022-12-02 长沙驰芯半导体科技有限公司 Multi-order multi-band anti-interference intelligent ultra-wideband antenna self-adaptation method
CN115425998B (en) * 2022-11-08 2023-02-10 长沙驰芯半导体科技有限公司 Multi-order multi-frequency-band anti-interference intelligent ultra-wideband antenna self-adaption method

Also Published As

Publication number Publication date
TWI738575B (en) 2021-09-01
TW202222034A (en) 2022-06-01

Similar Documents

Publication Publication Date Title
US7003265B2 (en) System and method for filtering signals in a transceiver
US8649532B2 (en) Electronic volume circuit
CN114553168A (en) Filter circuit
US8335328B2 (en) Programmable integrated microphone interface circuit
WO2004095700A2 (en) Reconfigurable baseband filter
US10797736B2 (en) Radio-frequency power amplification circuit and radio-frequency mode adjustment method
WO2006117943A1 (en) Radio filter circuit and noise reducing method
CN100495913C (en) DC bias cancel circuit
CN106658298B (en) Bass enhancement processing circuit and terminal equipment
CN100583629C (en) Simplified Sallen-Key low-pass filter circuit
US8797097B2 (en) Filtering device with low-pass filtering function and band-pass filtering function
CN113078923B (en) Signal transmission network, chip and signal processing device
CN113054913B (en) high frequency circuit
CN105515537B (en) Multi-frequency tunable low-noise amplifier and multi-frequency tuning implementation method thereof
US20020102001A1 (en) Sound quality regulation apparatus
CN111082755B (en) Low noise amplifier
CN109302203B (en) Radio frequency front end port multiplexing circuit
CN110011639B (en) Circuit with high-pass filter
CN113330684A (en) Configurable micro-acoustic RF filter
KR100755614B1 (en) Dc offset cancellation circuit and programmable gain amplifier using it
CN113472315A (en) Active filter circuit based on operational amplifier chip
CN210518234U (en) Intermediate frequency gain control circuit
US5760728A (en) Input stage for an analog-to-digital converter and method of operation thereof
US20230179156A1 (en) Signal receiving apparatus and programmable gain amplifier having mode-switching mechanism
JPWO2006098059A1 (en) Antenna damping circuit and high frequency receiver using the same

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
CB02 Change of applicant information

Address after: Science Park, Hsinchu, Taiwan, China Road 6-5, building 5

Applicant after: Dafa Technology Co.,Ltd.

Address before: Science Park, Hsinchu, Taiwan, China Road 6-5, building 5

Applicant before: AIROHA TECHNOLOGY CORP.

CB02 Change of applicant information