Introduction
Electric vehicles are becoming more
and more popular. On-board chargers (OBC) are important to charge the vehicle
battery safely and smartly. Most of the time, OBC is in sleep mode. The OBC wakes up
and functions after detecting signals from the charging gun. Based on the GB/T
18487.1-2015 standard, there are two types of required signals for AC charging gun
detection. The CC signal determines the connection status between the OBC and the
charging gun, and the CP signal determines the valid voltage and duty cycle status
of the AC power supply.
To detect the CC and CP signals,
determine the normal status, and wake up the host MCU to control the charging
process, some designs leverage discrete designs with transistors, resistors and
capacitors. However, it can be difficult to make changes for different project
requirements and can require different PCB sizes. Now, a user can leverage a MSPM0
MCU to design a lower-power and higher-scalability integrated OBC wake-up
design.
Why build an integrated design
with MSPM0?
- Low power: MSPM0 supports less
than 1μA of standby current.
- High scalability: satisfies
different requirements of wake-up delay time, condition, and source with
flexible software design compared to fixed discrete hardware design.
What can MSPM0 do in an OBC
wake-up design?
- Detect the resistance value of
the CC port to check the connection status between the OBC and the charging gun
by using an ADC or comparator module.
- 12-bit SAR ADC with
11.2ENOB and 1.68MSPS sampling rate.
- Two mode (low power and
high speed) comparator with an 8-bit reference DAC.
- Detect the voltage and duty cycle
values of the CP port to find the valid wake-up status by using ADC and timer
modules.
- Four 16-bit timers that
support low-power operation in standby mode.
- Enable the LDO for the host MCU
and wake the MCU up to control the charging process by using a GPIO.
- More functions such as
controlling PWM indicators, and conducting protocol translations with multiple
enhanced communication interfaces.
- Two UART interfaces that
support low-power operation in standby mode.
- Two I2C interfaces that
support wakeup from stop mode.
- One SPI supports up to
16Mbit/s.
Resources
Order a low-cost development kit LP-MSPM0L1306 to start designing an
integrated OBC wake-up design. Jump-start coding with a MSPM0-SDK software development kit and the SysConfig graphical code generation tool. The following links show
additional MSPM0 resources.
- Texas Instruments, MSPM0 overview page, product
page.
- Texas Instruments, MSPM0L130x-Q1 Automotive Mixed-Signal Microcontrollers,
data sheet.
- Texas Instruments, MSPM0 L-Series 32-MHz Microcontrollers Technical Reference
Manual, technical reference manual.
- Texas Instruments, MSPM0 L-Series Hardware Development Guide, application
note.
- Texas Instruments, MSPM0 Academy,
training.