Boost circuit and level shifter

Abstract

A level shifter including a first boost circuit, an inverter, a second boost circuit and a level shift circuit is disclosed. The first boost circuit receives an input signal, and a first amplification factor for the input signal is determined based on a control signal. The inverter receives the input signal to generate an inverted input signal. The second boost circuit is coupled to an output terminal of the inverter to receive the inverted input signal, and a second amplification factor for the inverted input signal is determined based on the control signal. The level shift circuit has a first input terminal and a second input terminal respectively coupled to output terminals of the first boost circuit and second boost circuit to change the voltage level of output signals from the first boost circuit and second boost circuit to a first voltage level.

1 . A boost circuit, comprising:
 a first transistor, having a first source, a first gate and a first drain, wherein the first source is coupled to a voltage source;   a second transistor, having a second source, a second gate and a second drain, wherein the second drain is coupled to the first drain, the second source is grounded, and the second gate is coupled to the first gate to receive an input signal;   a capacitor module, having a first terminal and a second terminal, controlled by a control signal to change a capacitance of the capacitor module for changing the discharge time of the capacitor module, wherein the first terminal is coupled to the first drain and the second drain;   a third transistor, having a third source, a third gate and a third drain, wherein the third source is coupled to the voltage source, and the third gate is coupled to an output terminal;   a fourth transistor having a fourth source, a fourth gate and a fourth drain, wherein the fourth gate receives the input signal, the fourth source and the third drain are coupled to the second terminal of the capacitor module, and the fourth drain is coupled to the output terminal; and   a fifth transistor, having a fifth source, a fifth gate and a fifth drain, wherein the fifth gate receives the input signal, the fifth drain is coupled to the output terminal, and the fifth source is grounded.   
   
   
       2 . The circuit as claimed in  claim 1 , wherein the capacitor module includes a first capacitor and a second capacitor, the first capacitor is further coupled to a switch device, and the first capacitor is connected in parallel to the second capacitor in response to the switch device is turned on based on the control signal. 
   
   
       3 . The circuit as claimed in  claim 2 , wherein the first capacitor and the second capacitor are made up of transistors. 
   
   
       4 . The circuit as claimed in  claim 2 , wherein the switch device is a transmission gate. 
   
   
       5 . A Level shifter, comprising:
 a first boost circuit for receiving an input signal, and determining a first amplification factor of the input signal based on a control signal;   an inverter for receiving the input signal to generate an inverted input signal;   a second boost circuit coupled to an output terminal of the inverter to receive the inverted input signal and to determine a second amplification factor of the inverted input signal based on the control signal; and   a level shift circuit having a first input terminal and a second input terminal respectively coupled to output terminals of the first boost circuit and second boost circuit to change the voltage level of output signals from the first boost circuit and second boost circuit to a first voltage level.