The standby voltage is generated yesteryear a ability provide circuit inside the principal ability converter. This became widely used inwards 1995 when the ATX specification was published to let a desktop figurer to hold upwards seat into a sleep-mode to salve energy. The standby voltage supplies a minor amount of ability to the motherboard enabling the figurer to rapidly restart, rather than performing a full, lengthy, kicking cycle. The term “standby” is oft confused amongst an auxiliary output, which has a dissimilar function.
A standby voltage is generated yesteryear a dissever switching circuit in addition to is non affected yesteryear the utilization of the remote on/off scream for or fifty-fifty an overload status on the principal output of the ability supply. A typical block diagram is shown below.
Figure 1 Block diagram of a typical ability provide amongst a standby output
The principal in addition to the standby switching converters part the high voltage output voltage (typically roughly 380Vdc) from the rectifier & PFC circuit. This saves terms yesteryear non duplicating the rectification in addition to filtering components. It tin hand notice hold upwards seen that they are independent of each other in addition to the remote on/off command is alone applied to the principal converter.
The auxiliary output is supplied from an additional winding on the principal converter transformer. If the principal output is turned off yesteryear the remote on/off, the auxiliary output volition likewise plow off. An auxiliary output is oft used to ability an external cooling fan if the ability provide has a forced air cooling rating. In this illustration if the auxiliary output is non introduce when the ability provide output is inhibited, it does non thing equally the principal converter volition non hold upwards providing whatever charge in addition to volition non postulate additional cooling.
Figure ii demonstrates how the diverse outputs in addition to business office interact amongst each other. If air conditioning ability is removed for whatever pregnant length of fourth dimension (10-50ms), in addition to hence of course of education all the outputs on the ability provide halt functioning.
Figure ii – Timing diagram
Many ability provide designers likewise utilization the standby converter to ability whatever “housekeeping” circuitry on the output of the principal converter. This allows an “enable” type remote on/off to hold upwards offered, where the scream for is pulled depression to activate the principal converter. Without a standby circuit, an external voltage has to hold upwards applied to the remote on/off to inhibit the ability supply.
Manufacturers of mid to high ability converters amongst a standby voltage volition oft country the off-load ability draw, or off-load ability consumption, amongst the remote on/off activated from the standby voltage.
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