Holtek announces its new Flash type fan controller, the HT45FM2C device, featuring 4Kx15 of Flash program memory, 256 bytes of RAM data memory, 128 bytes of Data EEPROM, a 4.5~5.5V operating voltage range and an operating frequency of up to 20MHz. The device also includes an internal high accuracy RC oscillator and a 9 channel 10-bit analog to digital converter. An 8-bitx2 remote timer can be used to decode IR signals as well as a PWM speed control interface. These functions are complemented by four 10-bit and one 16-bit CTM timers. A 16-bit capture timer is used as a fixed speed speed loop monitor. Integrated LVD and LVR functions, which can generate a reset when the power supply voltage falls below the minimum level for proper system operation, provide an additional safeguard to ensure stable operating under low power supply voltage conditions.
Being specifically directed at the Brushless Motor application area, the HT45FM2C device fully supports the most common six-step control in Hall Sensor and Sensor-less solutions, provides six external interrupt pins, among which three of them are used to sense the transmitted rotational signals from external Hall Effect Sensors, reducing the software loading on rotation positional sensing. Other features include three pairs of 10-bit PWM complimentary outputs complete with a Dead Time function, Polarity IO polarity adjustment and integrated Hall Sensor decoder for convenient control of three phase brushless DC motors. To ensure correct Brushless DC Motor control, it is also necessary to process some form of feedback signal which can sense and protect against situations of over-current and over-voltage. In this regard, the HT45FM2C has a fully integrated operational amplifier, a comparator and a DAC circuit which can be used to amplify the DC motor current detect signal. The combination of the operational amplifier, comparator and A/D converter can be used together to ensure smooth rotational control as well as implementing protection features.
The HT45FM2C is available in 28-pin SOP, 28-pin SSOP and 44-pin QFP package types making it suitable for three phase Brushless DC Motor Fan applications. As is the case with other Holtek 8-bit MCU devices, the HT45FM2C meets with industrial specifications and has excellent noise immunity characteristics.
