ACT4530

Rev 1.0, 19-Nov-2018

- 6 -

www.active-semi.com

Copyright © 2018 Active-Semi, Inc.

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.

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.

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.

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.

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.

Output Over Voltage Protection

Device stops switching when output over-voltage is

sensed, and resumes operation automatically when

output voltage drops to OVP- hysteresis.