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MCUs for single-,dual-cell Li-Battery Backup Power

12 Dec 2012

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Holtek Microelectronics has recently released its latest batch of flash MCUs. Holtek's HT45FH4M is a device designed for dual cell Lithium battery backup applications, while its HT45F4M caters to single-cell Li-battery backup power applications.

Included within the HT45FH4M features are a Flash Program capacity of 2Kx16, 128B of Data RAM, 64B of Data EEPROM, an internal 5V LDO output and two level shifters. Additional features include an optimal system frequency selection of 30MHz/4, a fully internal high accuracy 30MHz RC oscillator, an internal 8-channel 12bit A/D converter, a single 10bit Timer for generating complementary PWM outputs which can be used for DC/DC step-up or step-down applications and a single 16bit Timer. Protection features are provided in the way of over voltage and over current protection as well as Low Voltage Detection (LVD) and Low Voltage Reset function (LVR) for system voltage monitoring. If the system voltage falls below the LVR value, the LVR will automatically reset the device to avoid any unstable operation.

The HT45FH4M is specially designed for dual-cell Li-battery backup power products, it contains much of the necessary circuitry to implement such applications. It fully supports Li-battery charge and discharge operations. The maximum Li-ion dual cell voltage of 8.4V can be supplied to the internal 5V LDO input which can be used as the power supply for the HT45FH4M 5V LDO. The device provides an auto-detect external charger power connect function as well as an auto detect external discharge device connect function. Here, the over voltage protection circuitry input pin is used to detect whether an over voltage condition exists when the battery is undergoing a charge or discharge operation. The over current protection circuitry input pin is used to detect whether an over current situation exists. Complementary PWM outputs and level shifters are used to produce the dual Li-ion cell voltage to drive the external PMOS and NMOS transistors directly which can reduce the PMOS and NMOS channel impedance. By providing a synchronous rectification function during charging or discharging, power consumption is reduced and also enhances the dual-cell Li-battery backup power operating efficiency.

Meanwhile, the HT45F4M Single-cell Li-battery backup power MCU features includes a system frequency selection of 30MHz/4, a fully internal high accuracy 30MHz RC oscillator, an internal 8-channel 12bit A/D converter, a single 10bit Timer for generating complementary PWM outputs which can be used for DC/DC step-up or step-down applications and a single 16bit Timer. Protection features are provided in the way of over voltage and over current protection as well as Low Voltage Detect (LVD) and Low Voltage Reset functions (LVR) for system voltage monitoring. If the system voltage falls below the LVR value, the LVR will automatically reset the device to avoid any unstable operation.

The HT45F4M fully supports Li-battery charge and discharge operations, provides an auto-detect external charger power connect function as well as an auto detect external discharge device connect function. Here, the over voltage protection circuitry input pin is used to detect whether an over voltage exists on either of the input or output USB power interfaces when the battery is undergoing a charge or discharge operation. The over current protection circuitry input pin is used to detect whether an over current situation exists. Complementary PWM outputs are used to drive the external PMOS and NMOS transistors directly, thus providing a synchronous rectification function during charging or discharging to reduce power consumption and enhance the single-cell Li-battery backup power operating efficiency.

The HT45FH4M is supplied in a 20-pin SSOP package type and is suitable for dual-cell Li-battery backup power applications. In addition, this new device meets with industrial specifications and has excellent noise immunity as is the case with other Holtek 8bit MCUs.

The HT45F4M is supplied in 16-pin NSOP and 20-pin SSOP packages and is suitable for single-cell Li-battery backup power applications. In addition, this new device meets with industrial specifications and has excellent noise immunity as is the case with other HOLTEK 8bit MCUs.

The Datasheet for the HT45FH4M is available here.

The Datasheet for the HT45F4M is available here.




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