88EM8040/88EM8041
Datasheet
3.2
Signal Process and Functions
The 88EM8040/88EM8041 boost power board includes three inputs:
Resistive divider signal from AC line voltage
Feedback from the output DC bus
Voltage across the current sense resistor
The input phase voltage to ground (half rectified sine wave) scaled down by the input resistive
divider is applied to pin VIN. This signal used for estimation of the AC line voltage and regeneration
of the AC sine wave. It is also used for voltage level detection that produces adaptive multiple
thresholds for the over current limit and guarantees a constant power limit from the AC source.
Signal from the DC bus voltage through the muxed 12-bit Analog-to-Digital Converter (ADC)
provides the feedback data for the voltage PI control loop.
HF switching current pulse signal is retrieved from the voltage drop across the current sense resistor
that is negative to GND. This signal after HF noise filter and fixed gain amplification, is transferred
through the muxed 12-bit ADC to the digital current loop and the current error amplifier. The
reference current for the current control PI loop is provided by multiplying the voltage error amplifier
output and the regenerated sinusoidal line voltage information.
Doc. No. MV-S104983-01 Rev. A
Page 20
Copyright © 2009 Marvell
Document Classification: Proprietary
October 5, 2009, Preliminary
MARVELL [ MARVELL TECHNOLOGY GROUP LTD. ]
