Intelligent Power
Level 2 Intelligent Power Integration: Proportional Control
This integration level adds additional digital control to the standard analog design and Level 1 basic control features to actively adjust the output voltage, voltage limits, current limits and thermal limits. At this level, most of the operating parameters of the analog power supply can be digitally controlled and monitored. For instance, the output voltage can be fine-tuned to provide coordination between multiple power supplies in a system. Depending on the system I/O requirements, 8-bit solutions in the PIC12, PIC16 or PIC18 device families can provide good performance, while larger systems may require the flexibility of our 16-bit PIC24 family.
Level 2 Integration Example
A Level 2 control system has much greater integration with the power supply and allows better power supply environment monitoring. Integrated comparators can also be used to ensure fast response to system events or faults. A PWM peripheral is used to provide direct control of the analog PWM circuitry of the power unit, and can control the power-up conditions to provide soft-start. The MCU can monitor the power supply input current during the soft-start to ensure that components are not over-stressed. Serial communication peripherals allow coordination from a host device, control and monitoring of cooling fans and temperature sensors.
Control
- On-Off only, typically via a SHUTDN input to a traditional analog
Switch Mode Power Supply (SMPS) controller - Proportional control of the SMPS performance, such as output voltage and current
Monitoring:
- Current in/out
- Voltage in/out
- Temperature
- PWM
Features Possible:
- Level I features
- Soft-start and voltage slew rate control
- Digital temperature compensation
- Sample and hold calibration to an external standard
- Single or multiple preprogrammed output voltages
- Remote monitoring and control
Analog Access Requirements
- Shutdown and startup control through a SHUTDN input
- Control of reference inputs such as PWM clock, VREF, and ILIMIT
- Analog, digital and frequency based signals for monitoring
Reliability
The bulk of the reliability of the system is still determined by the traditional analog SMPS design. However, absolute performance specifications are regulated by the microcontroller and can lead to performance failures in the event of a software failure of the system.
