Demonstration circuit DC3004A is a 40V 4-SW Buck-Boost Controller configured for automotive USB-C PD charging applications supporting up to 60W output power capability featuring the LT8253. It powers devices connected through the USB-C port at voltages between 3.3V and 21V at up to 3A when VIN is between 9V and 18V. DC3004A will run down to 6VIN with reduced output power capability and can operate through up to 36V input transient conditions. DC3004A runs at 400kHz switching frequency and features spread spectrum frequency modulation (SSFM) for reduced EMI. With SSFM enabled, EMI generated by DC3004A falls below the CISPR 25 Class 5 limits.
The LT8253 has an operating input voltage range of 4V to 40V. It can regulate an output as a boost, a buck, or a 4-switch buck-boost controller. It has an adjustable switching frequency between 150kHz and 650kHz, with an option for external frequency synchronization or ±15% spread spectrum frequency modulation.
DC3004A utilizes Cypress Semiconductor’s CCG3PA USB-C port controller (CYPD3196) to interface between connected USB-C devices and the LT8253 power circuitry in order to comply with the latest USB Type-C and PD standards. This port controller device is powered directly from the INTVCC pin of the LT8253. The CCG3PA facilitates the power contract negotiation between the connected device and DC3004A and adjusts the voltage at the FB divider to set the output voltage accordingly. The LT8253+CCG3PA system monitors input voltage, output voltage and current, and measured temperature on board to help adjust output power capabilities based off measured operation parameters, as well as provide output over-voltage, under-voltage, and over-current protection.
The demo circuit is preloaded with firmware configured to support output power delivery up to 60W using the latest USB PD 3.0 protocol, and offers the following PDO/PPS output configuration options:
- PDO: 5V AT 3A, 9V AT 3A, 15V AT 3A, 20V AT 3A
- PPS: 3.3-11V AT 3A, 3.3-16V AT 3A, 3.3-21V AT 3A
DC3004A firmware is also configured to support legacy charge profiles including BC 1.2, QC 4.0 & 3.0, AFC, and Apple 2.4A charging. Firmware can be updated to support different PDO voltage and power levels. Contact factory apps for support.
The LT8253 datasheet gives a complete description of the part, operation, and applications information. The datasheet must be read in conjunction with this demo manual for DC3004A. The LT8253JUFDM is assembled in a 28-lead plastic side-wettable QFN (UFDM) package with a thermally-enhanced exposed ground pad. Proper board layout is essential for maximum thermal performance. See the datasheet section “PC Board Layout Checklist”.