Grid voltage bootstrap switch circuit

Abstract

The invention provides a grid voltage bootstrap switch circuit, and belongs to the field of analog integrated circuits. A charge pump circuit is used for charging a fifth capacitor and a sixth capacitor to make the stored charge amounts be constant, a grid voltage boosting circuit and a grid voltage reducing circuit are used for changing the grid voltages of an NMOS switch tube and a PMOS switch tube to maintain the grid voltages as constant values, and a switching circuit is used for controlling the charging of the charge pump circuit and the opening and closing of the grid voltage boosting circuit and the grid voltage reducing circuit. The grid voltage bootstrap switch circuit provided by the invention uses the NMOS switch tube and the PMOS switch tube to connect input signals to the output at the same time, thereby reducing the on-resistance of the switch; by using a parallel connection mode of the NMOS switch tube and the PMOS switch tube, the channel charge injection effects of the NMOS switch tube and the PMOS switch tube caused by clock changes cancel each other, and the clock feedthrough effects cancel each other as well, thereby improving the linearity of the switch; and by using a diode to charge the capacitor, the circuit does not have an overvoltage device, thus improving the reliability of the circuit.

Description

technical field [0001] The invention belongs to the field of analog integrated circuit design, in particular to a gate voltage bootstrap switch circuit. Background technique [0002] With the continuous development of modern communication technology and the continuous improvement of people's requirements for communication speed, the frequency of analog signals in communication systems continues to increase, and the requirements for converting analog signals into digital signals continue to increase. Higher linearity when sampling an analog signal requires the use of a gate voltage bootstrap circuit. [0003] The traditional gate voltage bootstrap switch circuit structure such as figure 1 As shown, by the main switch tube M s and a gate voltage bootstrap circuit, where the gate voltage bootstrap circuit includes a capacitor C 7 ~C 8 and MOS transistor M 1 ~ M 11 . Its working principle is: [0004] (1) Off phase: when CLK is low and CLKB is high, M 3 conduction, C 7...

AI Technical Summary

Problems solved by technology

[0011] However, in a traditional gate voltage bootstrap circuit, M 2 The overvoltage state in the turn-off phase will cause reliability problems of the circuit and reduce the life of the circuit; generally, in order to realize fast sampling of high-speed signals, the on-resistance of the main switch tube is required to be very low, which leads to its large size , which makes the channel charge injection effect and clock feed-through effect of the main switch more serious, resulting in lower linearity of the main switch sampling

Images