Power Supply Group Operation - Keysight N5224B Series Service Manual

Theory of Operation

Power Supply Group Operation

Power Supply Group Operation
The A20 power supply assembly is a switching power supply operating at 103
kHz switching frequency. The input power ranges for the power supply are 90
to 132 Vac or 195 to 250 Vac. The power supply automatically senses the input
voltage and switches between these two ranges.
Supply voltages which oscillate between the two normal input
ranges of the autoranging line voltage input will damage the power
supply. In rare cases, this damage has become a user safety
concern. If unstable power levels are expected, the analyzer input
power must be buffered by a line conditioner.
The dc output voltages of the A20 power supply assembly are:
— +15 V analog
— +9 V analog
— +3.3 V analog
— +5.2 V analog
— +15 V standby (always on)
— +32 V analog
— −15 V analog
— −5.2 V analog
— −7 V analog
— +5.1 V standby
— +12 V digital
— +3.35 V digital
— +5.1 V digital
The +15 V standby supply remains on continuously whenever the power supply
is plugged in. This supply is used to provide power to front panel LEDs and
CPU components when the analyzer is turned off.
Keysight N5224B/25B Service Guide 5-57