ML4803IS-1 View Datasheet(PDF) - Micro Linear Corporation
Part Name
Description
MFG CO.
'ML4803IS-1' PDF : 13 Pages View PDF
ML4803
TYPICAL APPLICATIONS (Continued)
inductor. The VCC OVP comparator senses when this
voltage exceeds 16V, and terminates the PFC output drive
while disabling the VEAO current sink. Once the VEAO
current sink is disabled, the VEAO voltage will charge
unabated, except for a diode clamp to VCC, reducing the
PFC pulse width. Once the VCC rail has decreased to
below 16.2V the VEAO sink will be enabled, discharging
external VEAO compensation components until the steady
state voltage is reached. Given that 15V on VCC
corresponds to 400V on the PFC output, 16V on VCC
corresponds to an OVP level of 426V.
COMPONENT REDUCTION
Components associated with the VRMS and IRMS pins of a
typical PFC controller such as the ML4824 have been
eliminated. The PFC power limit and bandwidth does vary
with line voltage. Double the power can be delivered from
a 220 V AC line versus a 110 V AC line. Since this is a
combination PFC/PWM, the power to the load is limited
by the PWM stage.
VISENSE
VC1 RAMP
GATE
DRIVE
OUTPUT
Figure 10. Typical Peak Current Mode Waveforms
VOUT = 400V
RP
VEAO
4
RCOMP
CZERO
CCOMP
35µA
R1
VC1
C1
30pF
5V
+
COMP
–
GATE
OUTPUT
3 ISENSE
–4
VI SENSE
Figure 11. ML4803 PFC Control
10
February 1999
Share Link: 
