Shanghai Huahong Grace Semiconductor Manufacturing Corporation

Carrier Corporation

Chengwei Tang

Xin Wang

Hui Li

Tingcan Mi

Hai Tian

A method of shutting down a refrigeration system including: initiating a shutdown process of the refrigeration system; closing a first valve within a refrigerant circuit of the refrigeration system; operating a compressor within the refrigerant circuit; detecting a suction pressure within the refrigerant circuit; closing a second valve within the refrigerant circuit of the refrigeration system when the suction pressure is below a threshold suction pressure; and stopping operation of the compressor.

Refrigerant system operation sequences for leak prevention

A bias current circuit which includes: a main unit including first PMOS and NMOS transistors constituting a first current path, and second PMOS and NMOS transistors constituting a second current path together with a first resistor; an output unit; and a supply voltage adapting unit including a third MOS transistor, a pull-up current source and a pull-down current source. The third MOS transistor is connected between a first node to which gates of the first and second PMOS transistors are connected and a second node to which drains of the second NMOS and PMOS transistors are connected. The pull-up current source is mirrored to the first PMOS transistor and configured to provide a current equal to a current provided by the pull-down current source. The bias current circuit has an operating voltage range encompassing low-voltage band such that it is operable at high and low voltages.

Bias current circuit operating at high and low voltages

A band-gap reference circuit including: mirror current branch circuits, band-gap paths, and an operational amplifier. Each mirror current branch circuit includes a mirror PMOS transistor and an auxiliary PMOS transistor. A drain of each mirror PMOS transistor is connected with a source of a corresponding auxiliary PMOS transistor, and a drain of said each auxiliary PMOS transistor is connected to a top end of a corresponding band-gap path, each gate of each mirror PMOS transistor is connected with an output port of the operational amplifier. A gate of each auxiliary PMOS transistor is connected to a first bias voltage. A substrate electrode of each mirror and auxiliary transistor is all connected to a source voltage. The output port of the operational amplifier outputs a high level less than the source voltage, the first bias voltage is less than an output voltage signal of the operational amplifier.

Growing community of inventors

Shanghai, China

Chengwei Tang