ACT4530
Rev 1.0, 19-Nov-2018
FUNCTIONAL BLOCK DIAGRAM
FUNCTIONAL DESCRIPTION
The ACT4530 is wide input range (40V) buck
converter that is optimized for CLA (cigarette lighter
adapter) car charger applications. It operates at
125kHz for automotive EMI compatibility. It supports
all major communication protocols including Q2.0,
USB PD, Apple, Samsung, and BC1.2. It requires
very few external components, resulting in small
solution sizes.
When PDC is pulled high or low, the PDC input
takes priority over any DP and DM communication.
DP and DM communication requests are only
accepted when PDC is floating.
Output Current Sensing and Regulation
The output current sense resistor is connected
between CSP and CSN. The sensed differential
voltage is compared with an internal reference
voltage to regulate the maximum output current. CC
loop and CV loop are in parallel. The current loop
response has a slower response compared to
voltage loop. During load current transients, the
inductor current can be up to +/-25% higher than
steady state condition. The customer should
confirm that the inductor does not saturate during
these peak conditions.
Improved QC2.0 Functionality (DP and
DM communication)
The ACT4530 implements an improved QC2.0
functionality. It overcomes the typical issues seen
with 12V automotive QC2.0 applications that
request a 12V output. A typical buck converter
cannot deliver a 12V output voltage from a 12V
input voltage. The typical buck converter goes to
maximum duty cycle and is unable to accurately
regulate the output voltage or current. The
ACT4530 resolves this issue by accepting all QC2.0
voltage requests, but it only responds to 5V and 9V
requests. Any 12V request is ignored, and the
output voltage does not change.
Cycle-by-Cycle Current Control
The conventional cycle-by-cycle peak current mode
is implemented with high-side FET current sense.
Input Over Voltage Protection
The converter is disabled if the input voltage is
above 42V (+/-2V). Device resumes operation
automatically 40ms after OVP is cleared.
PDC Pin
The PDC pin is an optional input that allows
external controllers to program the ACT4530 output
voltage. This pin is typically used in USB PD
applications. Opening PDC (floating input)
programs Vout to 5.1V. Pulling PDC low programs
Vout to 9.1V. Pulling PDC high does not change the
previously programmed output voltage. Starting the
IC with PDC already pulled high results in Vout
starting at 5V.
Output Over Voltage Protection
Device stops switching when output over-voltage is
sensed, and resumes operation automatically when
output voltage drops to OVP- hysteresis.
Innovative PowerTM
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