HT45F5Q-2A

General Information

The HT45F5Q-2A is a Flash Memory A/D type 8-bit high performance RISC architecture microcontroller especially designed for battery charger applications.

For memory features, the Flash Memory offers users the convenience of multi-programming features. Other memory includes an area of RAM Data Memory as well as an area of Emulated EEPROM memory for storage of non-volatile data such as serial numbers, calibration data etc.

Analog feature includes a multi-channel 12-bit A/D converter function. An extremely flexible Timer Module provides timing, pulse generation and PWM generation functions. Communication with the outside world is catered for by including a fully integrated UART interface function, which provides designers with a means of easy communication with external peripheral hardware. Protective features such as an internal Watchdog Timer and Low Voltage Reset coupled with excellent noise immunity and ESD protection ensure that reliable operation is maintained in hostile electrical environments.

A full choice of internal low and high speed oscillators is provided including two fully integrated system oscillators which require no external components for their implementation. The ability to operate and switch dynamically between a range of operating modes using different clock sources gives users the ability to optimise microcontroller operation and minimise power consumption.

For AC/DC charger applications, the device includes a battery charger management module, which can be used for the constant voltage and constant current closed loop charging control. The device therefore reduces the need for the usually required external TL431 component, operational amplifier and resistance analogic D/A Converter in traditional battery charging circuits. Therefore the peripheral circuit is more reduced, resulting in a smaller PCB area.

The charger management module is composed of two parts. The first part contains two groups of OPAs and D/A Converters, which are used to control the charging voltage and current. The upper limit value of the charger constant current and constant voltage can be obtained by configuring the D/A Converters in the software. The 14-bit D/A Converter is used for constant current control while the 12-bit D/A Converter is used for constant voltage control. The second part of the charger management contains a fixed gain operational amplifier which is used for current amplification. This improves the current resolution and allows the use of smaller current detection resistors thus reducing the resistor power consumption.

The D/A Converter in the charger management module is not only used for setting charging voltage and current, but also can be used together with the specific charger production fixtures for improving the traditional manual calibration techniques. By using the external production fixtures, the charger current voltage/current conditions can be confirmed. If the margin of errors is exceeded, the MCU will correct the error by fine tuning the D/A Converter, and store the corrected parameters to Emulated EEPROM. When the charger is recharged, the D/A Converter will be given a new correction value to implement correction purpose. Refer to the Holtek application notes for more details.

The inclusion of flexible I/O programming features, Time Base functions along with many other features, further enhance device functionality and flexibility for wide range of application possibilities.