Narrow pulse pull-down current type level displacement circuit

Abstract

The invention belongs to the field of electronic technology and relates to an integrated level shift circuit. It is mainly composed of seven circuit units including input buffer 1, constant current source switches A and B, pulse self-generation A and B, gate pull-down 6 and inverter 7. The low logic signal IN generates two control signals S1 and S2 of the same phase and reverse phase through the input buffer 1, which are used to control the constant current source switch A and control the constant current source switch B to obtain constant current output signals S3 and S4; The narrow pulse pull-down currents S5 and S6 are obtained from the self-generated A and pulse self-generated B circuits; then the floating level shift signal S7 with a level of VB~VH is generated by the gate pull-down 6 circuit, and after S7 passes through the inverter 7, it is in the inverter A high logic signal Vout-VB that is synchronous and in-phase with the low logic signal IN is generated between the output terminal of the phaser 7 and the high-side floating ground VB. The invention has the characteristics of simple circuit, low requirement for devices, low self-power consumption, no false trigger phenomenon, stable working state, easy integration and suitable for high-voltage application.

Description

technical field [0001] The invention belongs to the field of electronic technology, relates to an integrated level shift circuit, and simultaneously relates to a driving circuit of a floating high-end MOS switch. Background technique [0002] In the intelligent power integrated circuit of the bridge power switch structure, the high-side bridge arm and the low-side bridge arm are composed of power MOS or IGBT. The driving of the high-side bridge arm has the following basic requirements: First, the lower logic level compatible with CMOS / TTL logic needs to be shifted to the high logic level that can drive the power switch. Second, in order to make the working states of the high-side and low-side MOS switches symmetrical, the same logic level as that of the low-side MOS switch must be provided between the gate and source of the high-side MOS switch. However, in the switching process of the high-side bridge arm, the source potential of the power MOS used as a high-side switch fl...

AI Technical Summary

Problems solved by technology

However, since the rising edge and falling edge of the control signal are converted into narrow pulses respectively, the circuit is very complicated

In addition, the logic level on the high side is obtained directly from the voltage across the load resistor R1 or R2, and the displacement current when the power switch is turned on or off can easily generate voltage fluctuations on the load resistors R1 and R2, resulting in false trigger signals

Therefore, a certain pulse filter circuit must be used at the high voltage end to eliminate false trigger signals, which also increases the complexity of the circuit

[0007] To sum up, the currently used level shifting circuit has complex circuits, high device requirements, and is not suitable for high-voltage applications.

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