Title：Hybrid voltage mode and current mode PAM-4 (4-Level Pulse Amplitude Modulation) high-speed driving circuit

Country：中国

Patent No.：201910428411.3

Legal Status：Authorized

Inventor：Ziqiang Wang, Dengjie Wang, Hong Chen, Chun Zhang, Zhihua Wang

Assignee：Tsinghua University

Address：Tsinghua University,Haidian District Beijing 100084, China

Filing Date：2019-05-22

Issue Date：2020-12-08

The invention discloses a hybrid voltage mode and current mode PAM-4 (4-Level Pulse Amplitude Modulation) high-speed driving circuit, which comprises a voltage mode branch and a current mode branch, wherein the voltage mode branch comprises two input inverters (Mp1, Mn1, Mp2 and Mn2) and two series resistors R1; a differential input signal is (VMSBp and VMSBn); the current mode branch comprises anMp5 tube which serves as a bias current source, differential input pair tubes Mp3 and Mp4 and one pair of matching resistors R3, and a differential input signal is (VLSBp and VLSBn); the differentialoutput signal of the driving circuit is (Voutp and Voutn); and the input signal modulates the amplitude of an output level independently through a way of the voltage mode and the current mode so as to generate four levels. By use of the circuit, a traditional voltage mode driving circuit and a traditional current mode driving circuit are combined, and the voltage mode driving circuit serves as atwo-time weight branch so as to own good linearity and low power consumption. The current mode driving circuit serves as a one-time weight branch so as to enlarge the differential output amplitude ofoscillation of the driving circuit, and maximum differential output amplitude of oscillation can be 1.5 times of power supply voltage. 

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