A filter with process corner temperature compensation

Abstract

The present invention discloses a filter with process angle temperature compensation, comprising a fully differential operational amplifier, first to sixth resistor matrices, and first to third capacitors, wherein the first end of the first resistor matrix is connected to the positive differential input terminal, the second end of the first resistor matrix is connected to the first end of the third resistor matrix, the first end of the third capacitor, and the first end of the fifth resistor matrix, the first end of the second resistor matrix is connected to the negative differential input terminal, the second end of the second resistor matrix is connected to the first end of the fourth resistor matrix, the second end of the third capacitor, and the first end of the sixth resistor matrix, the second end of the third resistor matrix is connected to the positive input terminal of the amplifier and the first end of the first capacitor, the second end of the fourth resistor matrix is connected to the negative input terminal of the amplifier and the first end of the second capacitor, the second end of the fifth resistor matrix is connected to the second end of the first capacitor and the negative output terminal of the amplifier, and the second end of the sixth resistor matrix is connected to the second end of the second capacitor and the positive output terminal of the amplifier. The present invention can achieve good filtering characteristics.

Description

Technical Field

[0001] The invention belongs to the field of active RC filters, and in particular relates to a filter with process angle temperature compensation. Background Art

[0002] In an adjustable active RC filter, the bandwidth is determined by capacitance and resistance. In silicon-based processes, resistance varies significantly with temperature, with resistance values varying by 20% at different temperatures. Furthermore, during the tape-out process, resistance values vary by 40% at different process angles. This resistance deviation causes the bandwidth of existing filters to deviate by as much as two times at different process angle temperatures. In particular, the bandwidth drift of multi-stage filters significantly deteriorates their filtering characteristics. Summary of the Invention

[0003] The object of the present invention is to provide a filter with process angle temperature compensation, which can achieve relatively constant bandwidth of the filter at different process angle temperatures and achieve good filtering characteristics.

[0004] One aspect of the present invention provides a filter with process angle temperature compensation, comprising a fully differential operational amplifier, first to sixth resistor matrices, first to third capacitors, a positive differential input terminal, a negative differential input terminal, a positive differential output terminal, and a negative differential output terminal.

[0005] Among them, the first end of the first resistor matrix is connected to the positive differential input terminal, the second end of the first resistor matrix is connected to the first end of the third resistor matrix, the first end of the third capacitor, and the first end of the fifth resistor matrix, the first end of the second resistor matrix is connected to the negative differential input terminal, the second end of the second resistor matrix is connected to the first end of the fourth resistor matrix, the second end of the third capacitor, and the first end of the sixth resistor matrix, the second end of the third resistor matrix is connected to the positive input terminal of the fully differential operational amplifier and the first end of the first capacitor, the second end of the fourth resistor matrix is connected to the negative input terminal of the fully differential operational amplifier and the first end of the second capacitor, the second end of the fifth resistor matrix is connected to the second end of the first capacitor, the negative output terminal and the negative differential output terminal of the fully differential operational amplifier, and the second end of the sixth resistor matrix is connected to the second end of the second capacitor, the positive output terminal and the positive differential output terminal of the fully differential operational amplifier.

[0006] Preferably, the first resistor matrix to the sixth resistor matrix have the same resistor matrix structure, including 9 temperature compensation resistor pairs in parallel and 9 switches connected in series with the 9 temperature compensation resistor pairs respectively. Each temperature compensation resistor pair consists of two resistors with opposite temperature coefficients. The resistance value of the resistor matrix structure can be changed by selectively conducting the 9-way switch to compensate for the resistance value deviation at different process angle temperatures.

[0007] Preferably, the 9-way switches are the first switch to the ninth switch, wherein the first switch is turned on and the other switches are turned off, and the resistance value of the resistor matrix structure is R; the second switch is turned on and the other switches are turned off, and the resistance value of the resistor matrix structure is 19 / 20R; the third switch is turned on and the other switches are turned off, and the resistance value of the resistor matrix structure is 18 / 20R; the fourth switch is turned on and the other switches are turned off, and the resistance value of the resistor matrix structure is 17 / 20R; the fifth switch is turned on and the other switches are turned off, and the resistance value of the resistor matrix structure is 16 / 20R; the sixth switch is turned on and the other switches are turned off, and the resistance value of the resistor matrix structure is 15 / 20R; the seventh switch is turned on and the other switches are turned off, and the resistance value of the resistor matrix structure is 14 / 20R; the eighth switch is turned on and the other switches are turned off, and the resistance value of the resistor matrix structure is 13 / 20R; the ninth switch is turned on and the other switches are turned off, and the resistance value of the resistor matrix structure is 12 / 20R, wherein R is the maximum resistance of the temperature compensation resistor pair.

[0008] According to the filter with process angle temperature compensation according to the above aspect of the present invention, it is possible to achieve a relatively constant bandwidth of the filter at different process angle temperatures, thereby achieving good filtering characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive efforts.

[0010] Figure 1 is a schematic diagram of a filter with process angle temperature compensation according to an embodiment of the present invention;

[0011] Figure 2 1 is a schematic diagram of a resistor matrix according to an embodiment of the present invention. DETAILED DESCRIPTION

[0012] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0013] The embodiment of the present invention provides a filter with process angle temperature compensation, such as Figure 1As shown, the filter with process angle temperature compensation according to the embodiment of the present invention includes a fully differential operational amplifier FDA, 6 resistor matrices with the same structure (the first resistor matrix R matrix1 ~Sixth resistor matrix R matrix6 ), 3 capacitors (first capacitor C1 to third capacitor C3), positive differential input terminal Vin+, negative differential input terminal Vin-, positive differential output terminal Vout+ and negative differential output terminal Vout-.

[0014] The first resistance matrix R matrix1 The first end of the resistor matrix R is connected to the positive differential input terminal Vin+. matrix1 The second end and the third resistor matrix R matrix3 The first end of the third capacitor C3, the first end of the fifth resistor matrix R matrix5 The first end is connected to the second resistor matrix R matrix2 The first end of the resistor matrix R is connected to the negative differential input terminal Vin-. matrix2 The second end and the fourth resistor matrix R matrix4 The first end of the third capacitor C3, the second end of the sixth resistor matrix R matrix6 The first end is connected to the third resistor matrix R matrix3 The second end of the fourth resistor matrix R is connected to the positive input terminal of the fully differential operational amplifier FDA and the first end of the first capacitor C1. matrix4 The second end of the fifth resistor matrix R is connected to the negative input terminal of the fully differential operational amplifier FDA and the first end of the second capacitor C2. matrix5 The second end of the sixth resistor matrix R is connected to the second end of the first capacitor C1, the negative output end of the fully differential operational amplifier FDA, and the negative differential output end Vout-. matrix6 The second end of is connected to the second end of the second capacitor C2, the positive output end of the fully differential operational amplifier FDA, and the positive differential output end Vout+.

[0015] The first resistance matrix R matrix1 ~Sixth resistor matrix R matrix6 Together with the first capacitor C1 to the third capacitor C3, an RC network is formed. The value of the RC network determines the cutoff frequency, which is used to achieve different attenuation or enhancement effects on signals of different frequencies, that is, to achieve a filtering effect.

[0016] The first resistance matrix R matrix1 ~Sixth resistor matrix R matrix6 The resistor matrix structure is referred to as the resistor matrix R. matrix .like Figure 2 As shown, the resistance matrix R matrixThe device comprises nine temperature compensation resistor pairs connected in parallel and nine switches connected in series with each of the nine pairs. The compensation resistor pairs (R0, R1), (R2, R3), (R4, R5), ... (R18, R19) are composed of resistors with opposite temperature coefficients. R0, R2, R4, ... R18 have positive temperature coefficients, while R1, R3, R5, ... R19 have negative temperature coefficients. These two temperature coefficient resistor pairs are used to maintain a constant resistance value at different temperatures. Resistors with positive temperature coefficients increase in value as temperature increases, while resistors with negative temperature coefficients decrease in value. By connecting these two resistors in series, the resistance variation at different temperatures is eliminated, achieving a constant resistance value.

[0017] In this embodiment, 9 pairs of temperature compensation resistors are used to form a resistance matrix R matrix , bandwidth deviation ≤ 5% can be achieved, but the resistance matrix R matrix The number of resistor pairs can be more to achieve a smaller bandwidth offset, but the chip area will be larger.

[0018] The resistance matrix R is changed by selecting the conduction of the 9-way switch matrix The resistance value can compensate for the resistance deviation under different process angles. Assuming R is the maximum resistance of the resistors in the temperature compensation resistor pair (R0, R1), (R2, R3), (R4, R5), ... (R18, R19), then:

[0019] Switch S0 (first switch) is open, switches S1, S2, S3, S4, S5, S6, S7, S8, and S9 are closed, and the resistance value R is selected.

[0020] Switch S1 (second switch) is open, switches S0, S2, S3, S4, S5, S6, S7, S8, and S9 are closed, and the selected resistance value is 19 / 20R.

[0021] Switch S2 (the third switch) is open, switches S0, S1, S3, S4, S5, S6, S7, S8, and S9 are closed, and the selected resistance value is 18 / 20R.

[0022] Switch S3 (the fourth switch) is open, switches S0, S1, S2, S4, S5, S6, S7, S8, and S9 are closed, and the selected resistance value is 17 / 20R.

[0023] Switch S4 (fifth switch) is open, switches S0, S1, S2, S3, S5, S6, S7, S8, and S9 are closed, and the selected resistance value is 16 / 20R.

[0024] Switch S5 (the sixth switch) is open, switches S0, S1, S2, S3, S4, S6, S7, S8, and S9 are closed, and the selected resistance value is 15 / 20R.

[0025] Switch S6 (the seventh switch) is open, switches S0, S1, S2, S3, S4, S5, S7, S8, and S9 are closed, and the selected resistance value is 14 / 20R.

[0026] Switch S7 (the eighth switch) is open, switches S0, S1, S2, S3, S4, S5, S6, S8, and S9 are closed, and the selected resistance value is 13 / 20R.

[0027] Switch S8 (the ninth switch) is open, switches S0, S1, S2, S3, S4, S5, S6, S7, and S9 are closed, and the selected resistance value is 12 / 20R.

[0028] The filter of the above embodiment of the present invention adopts process angle temperature compensation technology, and realizes relatively constant bandwidth of the filter at different process angle temperatures through the resistor matrix, with a deviation rate of ≤5%, and has good filtering characteristics.

[0029] Specifically, compared to a traditional RC filter, the filter of the above embodiment of the present invention compensates for the resistance change of the resistance value at different temperatures through two resistor pairs with opposite temperature coefficients. At the same time, due to process deviations in the manufacturing process of semiconductor devices, these deviations include inconsistencies in doping concentration, diffusion depth, and etching degree, resulting in inconsistent drift velocity of carriers in the chip manufacturing process, thereby causing deviation in the resistance value, with a deviation rate of up to 40%. That is, in the manufacturing process of the same batch of chips, for example, a resistor with a resistance value of 1KΩ under a normal temperature tt process angle is manufactured with a resistance range of 0.8KΩ~1.2KΩ. By selecting 9 pairs of switch resistor matrices, a resistance selection of 0.75KΩ~1.25KΩ can be achieved, and the adjustment step is 1 / 20 R, that is, a resistance value deviation rate of ≤5% can be achieved, thereby enabling the filter to achieve good filtering characteristics.

[0030] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. A filter with process angle temperature compensation, characterized in that: The system comprises a fully differential operational amplifier, a first resistor matrix to a sixth resistor matrix, a first capacitor to a third capacitor, a positive differential input terminal, a negative differential input terminal, a positive differential output terminal and a negative differential output terminal. Wherein, a first end of the first resistor matrix is connected to the positive differential input terminal, a second end of the first resistor matrix is connected to the first end of the third resistor matrix, the first end of the third capacitor, and the first end of the fifth resistor matrix, a first end of the second resistor matrix is connected to the negative differential input terminal, a second end of the second resistor matrix is connected to the first end of the fourth resistor matrix, the second end of the third capacitor, and the first end of the sixth resistor matrix, a second end of the third resistor matrix is connected to the positive input terminal of the fully differential operational amplifier and the first end of the first capacitor, a second end of the fourth resistor matrix is connected to the negative input terminal of the fully differential operational amplifier and the first end of the second capacitor, a second end of the fifth resistor matrix is connected to the second end of the first capacitor, the negative output terminal of the fully differential operational amplifier, and the negative differential output terminal, and a second end of the sixth resistor matrix is connected to the second end of the second capacitor, the positive output terminal of the fully differential operational amplifier, and the positive differential output terminal; The first to sixth resistor matrices have the same resistor matrix structure, including 9 temperature compensation resistor pairs connected in parallel and 9 switches connected in series with the 9 temperature compensation resistor pairs. Each temperature compensation resistor pair consists of two resistors with opposite temperature coefficients. The resistance value of the resistor matrix structure can be changed by selectively conducting the 9 switches to compensate for the resistance value deviation at different process corner temperatures.

2. The filter with process angle temperature compensation according to claim 1, wherein: The 9-way switches are the first switch to the ninth switch, wherein when the first switch is turned on and the other switches are turned off, the resistance value of the resistor matrix structure is R; when the second switch is turned on and the other switches are turned off, the resistance value of the resistor matrix structure is 19 / 20R; when the third switch is turned on and the other switches are turned off, the resistance value of the resistor matrix structure is 18 / 20R; when the fourth switch is turned on and the other switches are turned off, the resistance value of the resistor matrix structure is 17 / 20R; when the fifth switch is turned on and the other switches are turned off, the resistance value of the resistor matrix structure is 16 / 20R; when the sixth switch is turned on and the other switches are turned off, the resistance value of the resistor matrix structure is 15 / 20R; when the seventh switch is turned on and the other switches are turned off, the resistance value of the resistor matrix structure is 14 / 20R; when the eighth switch is turned on and the other switches are turned off, the resistance value of the resistor matrix structure is 13 / 20R; when the ninth switch is turned on and the other switches are turned off, the resistance value of the resistor matrix structure is 12 / 20R, where R is the maximum resistance of the compensation resistor pair.

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