Data Sheet Rev. B, September 2019 | Subject to change without notice

6 of 15

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ACT4530M

40 V/3.0 A CV/CC Buck Converter Featuring QC2.0, USB Auto-Detect and USB-PD

FUNCTIONAL BLOCK DIAGRAM

FUNCTIONAL DESCRIPTION

The ACT4530M is wide input range (40 V) buck

converter that is optimized for CLA (cigarette lighter

adapter) car charger applications. It operates at

125 kHz 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 ACT4530M implements an improved QC2.0

functionality. It overcomes the typical issues seen with

12 V automotive QC2.0 applications that request a 12 V

output. A typical buck converter cannot deliver a 12 V

output voltage from a 12 V input voltage. The typical

buck converter goes to maximum duty cycle and is

unable to accurately regulate the output voltage or

current. The ACT4530M resolves this issue by accept-

ing all QC2.0 voltage requests, but it only responds to

5 V and 9 V requests. Any 12 V 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 ACT4530M output voltage.

This pin is typically used in USB PD applications.

Opening PDC (floating input) programs Vout to 5.1 V.

Pulling PDC low programs Vout to 9.1 V. Pulling PDC

high does not change the previously programmed

output voltage. Starting the IC with PDC already pulled

high results in Vout starting at 5 V.

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

42 V (+/-2 V). Device resumes operation automatically

40 ms 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.

FUNCTIONAL DESCRIPTION

Output Over Voltage Discharge

PWM

Controller

Driver

Current Sense

and Control

70mΩ

4.7Ω

OVP

CSP

CSN

GND

SW

HSB

UVLO

VIN

DP

DM

QC2.0

Detect

USB

Auto

Detect

PDC