Adjustable T-coil device for wideband input / output circuits

Abstract

A T-shaped coil device includes a capacitor unit, a first inductor unit, and a second inductor unit electrically connected to each other. The capacitor unit is electrically connected between a first node and a second node. The first inductor unit is electrically connected between the first node and a third node and includes a first inductor and a first modulation circuit for changing the inductance value of the first inductor. The second inductor unit is electrically connected between the second node and the third node. The third node is electrically connected to a load circuit. By changing the capacitance value of the capacitor unit and the inductance values ​​of the first and second inductor units, the capacitance and inductance values ​​of the T-shaped coil device can be flexibly adjusted according to different parasitic capacitance values ​​of the load circuit to obtain the most effective capacitance compensation.

Description

Technical Field

[0001] This invention relates to an electronic device for signal processing, and more particularly to a T-type coil device applicable to different usage scenarios. Prior Technology

[0002] Digital transmission interfaces are primarily used in computer systems, playing a crucial role in computation, transmission, storage, and display. With the active deployment of 5G and the widespread adoption of AI, the demand for high-speed transmission has increased dramatically, leading to a significant rise in the demand for high-speed peripheral component interconnect express (PCIe) devices.

[0003] When high-speed signals are transmitted through transmission lines, the higher the frequency of the high-speed signal, the more significant the gain attenuation becomes, which can even lead to signal distortion in severe cases. Therefore, ensuring signal quality is a very important issue. Summary of the Invention

[0004] Therefore, one object of the present invention is to provide a T-type coil device that can improve upon at least one of the disadvantages of the prior art.

[0005] Therefore, the T-type coil device of the present invention includes a capacitor unit, a first inductor unit and a second inductor unit that are electrically connected to each other.

[0006] The capacitor unit is electrically connected between a first node and a second node.

[0007] The first inductor unit is electrically connected between the first node and a third node, and includes a first inductor and a first modulation circuit for changing the inductance value of the first inductor.

[0008] The second inductor unit is electrically connected between the second node and the third node.

[0009] The advantage of this invention is that by changing the capacitance value of the capacitor unit and the inductance values ​​of the first inductor unit and the second inductor unit, the capacitance and inductance values ​​of the T-type coil device of this invention can be flexibly adjusted according to the parasitic capacitance values ​​of different load circuits, so as to obtain the most effective capacitance compensation and improve the application flexibility. Simple Explanation of the Diagram

[0010] Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: Figure 1 is a block diagram illustrating the electrical connection state of an embodiment of the T-type coil device of the present invention; Figure 2 is a circuit diagram illustrating the detailed circuit configuration of this embodiment in Figure 1; Figure 3 is a simulation result of the capacitance value of a capacitor unit in this embodiment relative to different bias voltage values; Figure 4 shows the first simulation results of an output signal relative to different operating frequencies when the parasitic capacitance of a load circuit is 430 fF. Figure 5 shows the second simulation results of the output signal relative to different operating frequencies when the parasitic capacitance of the load circuit is 630fF; Figure 6 shows the third simulation results of the output signal relative to different operating frequencies when the parasitic capacitance of the load circuit is 830 fF; and Figure 7 shows the fourth simulation result of the output signal relative to different operating frequencies when the parasitic capacitance of the load circuit is 1030fF. Implementation

[0011] Referring to Figures 1 and 2, one embodiment of the T-type coil device 100 of the present invention can be applied to a transmission path of an input device 91, an output device 92, and a load circuit 93 that are electrically connected to each other. The T-type coil device 100 of the present invention receives an input signal Vin from the input device 91 and outputs an output signal Vout to the output device 92. The input device 91 and the output device 92 may each include, but are not limited to, an amplifier circuit. The load circuit 93 may include, but is not limited to, an electrostatic discharge (ESD) protection circuit, and can be flexibly adjusted to different circuits according to the actual usage scenario. The load circuit 93 has a parasitic capacitance value, which may be different values ​​depending on the circuit in which the load circuit 93 is applied.

[0012] The T-type coil device 100 of the present invention includes a first node N1 electrically connected to the input device 91, a second node N2 electrically connected to the output device 92, a third node N3 electrically connected to the load circuit 93, a fourth node N4, a working voltage terminal providing a working voltage value VDD, a reference voltage terminal providing a ground voltage value GND, and a capacitor unit 3, a first inductor unit 1 and a second inductor unit 2 electrically connected between the first node N1 and the second node N2.

[0013] In this embodiment, the first node N1 is electrically connected to the input device 91, and the second node N2 is electrically connected to the output device 92. The input signal Vin and the output signal Vout may include, but are not limited to, radio frequency signals. In other embodiments, it can be implemented by electrically connecting the first node N1 to the output device 92 and the second node N2 to the input device 91.

[0014] In this embodiment, the operating voltage VDD is 1.8V and the grounding voltage GND is 0V.

[0015] The first inductor unit 1 includes a first inductor L11 electrically connected between the first node N1 and the third node N3, and a first modulation circuit 11 for changing the inductance value of the first inductor L11. The first modulation circuit 11 has a first modulation inductor L12 that is magnetically coupled to the first inductor L11, and a first current source 12 electrically connected to the first modulation inductor L12. In this embodiment, the first inductor L11 and the first modulation inductor L12 are the primary coil and the secondary coil, respectively.

[0016] The first modulation inductor L12 has a first terminal electrically connected to the first current source 12 and a second terminal electrically connected to the reference voltage terminal. The first current source 12 has a first current mirror 121 electrically connected to the operating voltage terminal and having a plurality of first output terminals, a plurality of first switches 122 respectively electrically connected to the first output terminals, and a first input transistor 123 for providing a first input current. The first output terminals are electrically connected to the first terminal of the first modulation inductor L12, and each first output terminal corresponds to one first switch 122. In this embodiment, there are two of each of the first output terminals and the first switches 122, but in actual applications, there can be one or more of them; the first input transistor 123 is an N-type metal-oxide-semiconductor field-effect transistor (N-MOSFET), and provides the first output current to the first current mirror 121 through its drain.

[0017] The first current mirror 121 generates several first output currents, each output from one of the first output terminals, based on the first input current. Each first switch 122 has a control terminal, a first terminal electrically connected to the corresponding first output terminal, and a second terminal electrically connected to the corresponding reference voltage terminal. In this embodiment, each first switch 122 is an N-type metal-oxide-semiconductor field-effect transistor, with its gate, drain, and source corresponding to the control terminal, the first terminal, and the second terminal, respectively. When an on-state voltage Von is applied to the control terminal of any first switch 122, the corresponding first output terminal outputs one first output current. Therefore, by adjusting the number of on-state voltages Von applied to the control terminals of the first switches 122, the number of first output currents output by the first current mirror 121 can be adjusted. The first modulation inductor L12 generates a corresponding inductance value based on the received first output currents, and mutually inducts with the first inductor L11 through magnetic coupling to change the inductance value of the first inductor L11.

[0018] The second inductor unit 2 includes a second inductor L21 electrically connected between the second node N2 and the third node N3, and a second modulation circuit 21 for changing the inductance value of the second inductor L21. The second modulation circuit 21 has a second modulation inductor L22 magnetically coupled to the second inductor L21, and a second current source 22 electrically connected to the second modulation inductor L22. In this embodiment, the second inductor L21 and the second modulation inductor L22 are the primary coil and secondary coil, respectively.

[0019] The second modulation inductor L22 has a first terminal electrically connected to the second current source 22 and a second terminal electrically connected to the reference voltage terminal. The second current source 22 has a second current mirror 221 electrically connected to the operating voltage terminal and having several second output terminals, several second switches 222 respectively electrically connected to the second output terminals, and a second input transistor 223 for providing a second input current. The second output terminals are electrically connected to the first terminal of the second modulation inductor L22, and each second output terminal corresponds to one second switch 222. There are two of each of the second output terminals and the second switches 222, but in actual applications there can be one or more of them; the first input transistor 123 is an N-type metal-oxide-semiconductor field-effect transistor, and provides the first output current to the first current mirror 121 through its drain.

[0020] The second current mirror 221 generates several second output currents from the second output terminals based on the second input current. Each second switch 222 has a control terminal, a first terminal electrically connected to the corresponding second output terminal, and a second terminal electrically connected to the corresponding reference voltage terminal. In this embodiment, each second switch 222 is an N-type metal-oxide-semiconductor field-effect transistor, and its gate, drain, and source correspond to the control terminal, the first terminal, and the second terminal, respectively. When the turn-on voltage Von is applied to the control terminal of any second switch 222, the corresponding second output terminal can output one second output current. Therefore, by adjusting the number of turn-on voltages Von applied to the control terminals of the second switches 222, the number of second output currents to be output by the second current mirror 221 can be adjusted. The second modulation inductor L22 generates a corresponding inductance value based on the received several second output currents, and mutually inducts with the second inductor L21 through magnetic coupling to change the inductance value of the second inductor L21.

[0021] The capacitor unit 3 is electrically connected between the first node N1 and the second node N2, and includes a capacitor C1 electrically connected between the first node N1 and the fourth node N4, and a variable capacitor C2 electrically connected between the second node N2 and the fourth node N4. The variable capacitor C2 can be implemented using, but is not limited to, an N-type metal-oxide-semiconductor field-effect transistor with a W / L of 5µm / 1µm, with its gate electrically connected to the fourth node N4, and its source and drain electrically connected to the second node N2. In the simulation of this embodiment, the capacitance value of capacitor C1 is 1pF. Referring to Figure 3, curve A illustrates that the overall capacitance value of the capacitor unit 3 ranges from approximately 20 to 73 fF. In other embodiments, the capacitor C1 and the variable capacitor C2 are interchangeable, that is, the capacitor C1 is electrically connected between the second node N2 and the fourth node N4, while the variable capacitor C2 is electrically connected between the first node N1 and the fourth node N4, and the variable capacitor C2 also adjusts its capacitance value by changing the bias voltage of the fourth node N4.

[0022] In this embodiment, the T-type coil device 100 of the present invention can compensate for parasitic capacitance values ​​ranging from 430 to 1030 pF. Referring to Figures 4, 5, 6, and 7, the simulation results of capacitance compensation with and without the use of the T-type coil device 100 of the present invention are illustrated for the parasitic capacitance values ​​of the load circuit 93 being 430 fF, 630 fF, 830 fF, and 1030 fF, respectively. Specifically, curves B11, B21, B31, and B41 illustrate the gain of the output signal Vout relative to different operating frequencies when capacitance compensation is not performed using the T-type coil device 100 of the present invention; curves B12, B22, B32, and B42 illustrate the gain of the output signal Vout relative to different operating frequencies when capacitance compensation is performed using the T-type coil device 100 of the present invention.

[0023] As shown in Figure 4, when the parasitic capacitance in the load circuit 93 is 430fF, the overall capacitance of the capacitor unit 3 is set to 23.75fF, and the inductance values ​​of the first inductor L11 and the second inductor L21 are both 316pH. Curve B11 shows that before capacitance compensation using the T-type coil device 100 of the present invention, the gain of the output signal Vout at an operating frequency greater than 3GHz has already attenuated to below 5dB; curve B12 shows that after capacitance compensation using the T-type coil device 100 of the present invention, the gain of the output signal Vout only attenuates to below 5dB at an operating frequency greater than 9GHz.

[0024] As shown in Figure 5, when the parasitic capacitance in the load circuit 93 is 630fF, the overall capacitance of the capacitor unit 3 is set to 36.25fF, and the inductance values ​​of the first inductor L11 and the second inductor L21 are both 483pH. Curve B21 shows that before capacitance compensation using the T-type coil device 100 of the present invention, the gain of the output signal Vout at an operating frequency greater than 2.5GHz has already attenuated to below 5dB; curve B22 shows that after capacitance compensation using the T-type coil device 100 of the present invention, the gain of the output signal Vout only attenuates to below 5dB at an operating frequency greater than 8GHz.

[0025] As shown in Figure 6, when the parasitic capacitance in the load circuit 93 is 830fF, the overall capacitance of the capacitor unit 3 is set to 48.75fF, and the inductance values ​​of the first inductor L11 and the second inductor L21 are both 650pF. Curve B31 shows that before capacitance compensation using the T-type coil device 100 of the present invention, the gain of the output signal Vout at operating frequencies greater than 1.9GHz has already attenuated to below 5dB; curve B32 shows that after capacitance compensation using the T-type coil device 100 of the present invention, the gain of the output signal Vout only attenuates to below 5dB at operating frequencies greater than 8.2GHz.

[0026] As shown in Figure 7, when the parasitic capacitance in the load circuit 93 is 1030 fF, the overall capacitance of the capacitor unit 3 is set to 61.25 fF, and the inductance values ​​of the first inductor L11 and the second inductor L21 are both 816 pH. Curve B41 shows that before capacitance compensation using the T-type coil device 100 of the present invention, the gain of the output signal Vout at an operating frequency greater than 1.5 GHz has already attenuated to below 5 dB; curve B42 shows that after capacitance compensation using the T-type coil device 100 of the present invention, the gain of the output signal Vout only attenuates to below 5 dB at an operating frequency greater than 8 GHz.

[0027] In summary, by biasing the variable capacitor C2 and applying different amounts of the turn-on voltage Von to the first switch 122 and the second switch 222, the capacitance value of the variable capacitor C2, as well as the inductance values ​​of the first inductor L11 and the second inductor L21, can be changed. This achieves the goal of flexibly adjusting the capacitance and inductance values ​​of the T-type coil device 100 according to different parasitic capacitance values ​​of the load circuit 93, effectively improving the gain of the output signal Vout, and obtaining the most effective capacitance compensation.

[0028] However, the above description is merely an embodiment of the present invention and should not be construed as limiting the scope of the present invention. Any simple equivalent changes and modifications made in accordance with the scope of the patent application and the contents of the patent specification shall still fall within the scope of the patent of the present invention.

[0029] 100: T-type coil device 1: First Inductor Unit L11: First Inductor 11: First modulation circuit L12: First regulating inductor 12: First Current Source 121: First Current Mirror 122: First Switch 123: First input transistor 2: Second Inductor Unit L21: Second Inductor 21: Second modulation circuit L22: Second regulating inductor 22: Second Current Source 221: Second Current Mirror 222: Second Switch 223: Second input transistor 3: Capacitor Unit C1: Capacitor C2: Variable capacitor 91: Input device 92: Output device 93: Load Circuit N1: First node N2: Second node N3: Third node N4: Fourth Node VDD: Operating voltage value GND: Grounding voltage value Vin: Input signal Vout: Output signal Von: Turn-on voltage A, B11, B12, B21, B22, B31, B32, B41, B42: Curves

Claims

1. A T-type coil device, comprising: a capacitor unit electrically connected between a first node and a second node; a first inductor unit electrically connected between the first node and a third node, including a first inductor and a first modulation circuit for changing the inductance value of the first inductor; and a second inductor unit electrically connected between the second node and the third node, wherein, The first modulation circuit has a first modulation inductor magnetically coupled to the first inductor, and a first current source electrically connected to the first modulation inductor, the first current source outputting an adjustable current to the first modulation inductor.

2. The T-type coil device as claimed in claim 1, wherein, The first modulation inductor has a first terminal and a second terminal electrically connected to a reference voltage terminal; the first current source has a first current mirror and a plurality of first switches; each of the first switches has a first terminal and a second terminal electrically connected to the reference voltage terminal; the first current mirror has a plurality of first output terminals respectively corresponding to the first switches, and generates a plurality of first output currents respectively output from the output terminals according to a first input current; each of the first output terminals of the first current mirror is electrically connected to the first terminal of the first modulation inductor and the first terminal of a corresponding one of the first switches.

3. The T-type coil device as claimed in claim 1, wherein, The second inductor unit includes a second inductor and a second modulation circuit for changing the inductance value of the second inductor.

4. A T-type coil device, comprising: a capacitor unit electrically connected between a first node and a second node; a first inductor unit electrically connected between the first node and a third node, including a first inductor and a first modulation circuit for changing the inductance value of the first inductor; and a second inductor unit electrically connected between the second node and the third node, wherein... The second inductor unit includes a second inductor and a second modulation circuit for changing the inductance value of the second inductor. The second modulation circuit has a second modulation inductor magnetically coupled to the second inductor and a second current source electrically connected to the second modulation inductor. The second current source outputs an adjustable current to the second modulation inductor.

5. The T-type coil device as claimed in claim 4, wherein, The second modulating inductor has a first terminal and a second terminal electrically connected to a reference voltage terminal; the second current source has a second current mirror and a plurality of second switches; each of the second switches has a first terminal and a second terminal electrically connected to the reference voltage terminal; the second current mirror has a plurality of second output terminals respectively corresponding to the second switches, and generates a plurality of second output currents respectively output from the output terminals according to a second input current; each of the second output terminals of the second current mirror is electrically connected to the first terminal of the second modulating inductor and the first terminal of a corresponding one of the second switches.

6. A T-type coil device, comprising: a capacitor unit electrically connected between a first node and a second node; a first inductor unit electrically connected between the first node and a third node, including a first inductor and a first modulation circuit for changing the inductance value of the first inductor; and a second inductor unit electrically connected between the second node and the third node, wherein... The capacitor unit includes a capacitor and a variable capacitor electrically connected between the first node and the second node.

7. The T-type coil device as claimed in claim 6, wherein, The variable capacitor has an N-type metal-oxide-semiconductor field-effect transistor.

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