Standby power supply circuit for 2-wire bus intercom system and apparatus thereof

摘要

The present invention discloses a standby power supply circuit for a 2-wire bus intercom system and an apparatus thereof. The standby power supply circuit is separated into two power supply modules; in which the first power supply module is a power supply to standby circuit and the second power supply module is a power supply to operation circuit; said power supply to operation circuit is switched off by a constant current switch when the device load is at the standby status; and said power supply to standby circuit comprises a constant current circuit whose alternating current impedance is very large. The solutions of the present invention achieve larger alternating current impedance for the 2-wire intercom system, which can offer sufficient power for many device loads both in the conditions of operation and standby statuses.

主权项

1. A standby power supply circuit for a 2-wire bus intercom system, wherein said standby power supply circuit is separated into two power supply modules, the standby power supply circuit comprising:
a first power supply module that is a power supply to a standby circuit and a second power supply module that is a power supply to an operation circuit; wherein said power supply to the operation circuit is switched off by a constant current switch when a device load is at a standby status; wherein said power supply to the standby circuit comprises a constant current circuit with an alternating current impedance; wherein said power supply to the standby circuit further comprises the constant current circuit connected between an input terminal and a standby regulator circuit; wherein said constant current circuit further comprises a main constant current circuit and an auxiliary constant current circuit, wherein said main constant current circuit stabilizes current through a main constant current path of said main constant current circuit; wherein said auxiliary constant current circuit offers a bias current for the main constant current circuit under a bias voltage while maintaining an AC impedance.