Patent ID: 8847661
Filing Date: 2014-09-30
Classification: H03K

Abstract:
1. A level shift device to convert an input signal having a first voltage level into an output signal having a second voltage level, the level shift device comprising: a latch-type level shifter comprising two upper pull-up P channel transistors and two lower P channel transistors to prevent gate-source voltage breakdown of the two upper pull-up P channel transistors, the two upper pull-up P channel transistors and two lower P channel transistors being configured in a latch structure, wherein the latch structure is each gate electrode of the two upper pull-up P channel transistor cross-connected to each drain electrode of the two upper pull-up P channel transistor, respectively; and a voltage generate unit to generate a predetermined voltage to prevent the gate-source voltage breakdown of the two upper pull-up P channel transistors and provide the predetermined voltage to gate electrodes of the two lower P channel transistors, wherein the voltage generate unit comprises: a Zener diode having an anode electrode connected to a gate electrode of one of the upper pull-up P channel transistor, a current source having a current input terminal connected to the anode electrode of the Zener diode, a capacitor having one terminal connected to the anode of the Zener diode and an opposite end connected to a ground, wherein the current source is connected to the capacitor in parallel, wherein the second voltage level is higher than the first voltage level.