Power Management IC's


A power management IC is an integrated circuit designed to serve a specific role in enhancing the way power is utilized by an electronic or electrical system.  Power management IC's therefore include devices that are used in the management of one or more of the following: 1) power generation; 2) power delivery; 3) power consumption; 4) power replenishment/storage; 5) power conservation; and 6) power monitoring.


The need for power management IC's became more emphasized as consumers embraced a more mobile life style. Suddenly, they wanted their laptops, cell phones, PDA's, and other mobile devices to last longer before requiring a battery recharge. This demand resulted in the vast array of power management IC's being offered in the market today, examples of which are presented below.  The descriptions of the IC's provided were taken from their respective manufacturers' websites, and are included here only to serve as an overview of what power management IC's are available to designers.


The MAX1702B, manufactured by Maxim, is triple-output power management IC for microprocessor-based applications that require substantial computing and multimedia capability at low power, such as PDAs, third-generation smart cellular phones, internet appliances, automotive in-dash Telematics systems, etc. The MAX1702B integrates three ultra-high-performance power supplies with associated supervisory and management functions.


Its power management functions include automatic power-up sequencing, power-on-reset and manual reset with timer, and two levels of low-battery detection.  The built-in DC-DC converters use fast 1MHz PWM switching, allowing the use of small external components. They automatically switch from PWM mode under heavy loads to skip mode under light loads to reduce quiescent current and maximize battery life. The input voltage range is from 2.6V to 5.5V, allowing the use of three NiMH cells, a single Li+ cell, or a regulated 5V input. The MAX1702B is available in a tiny 6mm x 6mm, 36-pin QFN package and operates over the -40C to +85C temperature range.


The AT73C202, manufactured by Atmel, is an ultra low-power Battery and Power Management IC designed for state-of-the-art cellular phones. Other power management devices manufactured by ATMEL include the AT73C203, an ultra low-power Battery and Power Management IC designed for portable and hand-held applications built around microprocessors requiring smart power management functions; and the AT73C204, an integrated power management solution for the add-on features in new-generation mobile phones, e.g., camera modules, sound systems, memory modules, Bluetooth modules, etc.   


Analog Devices (ADI) is another major company that produces a large selection of power management IC's. For instance, the ADP3806 is a stand-alone Li-Ion battery-charging IC that combines high output voltage accuracy with precise current control to improve the performance and reduce the design complexity of Constant-Current, Constant-Voltage (CCCV) chargers. Other examples of battery chargers from ADI are: the ADP2291 Compact, 1.5 A Linear Charger for Single-Cell Li+ Battery; the ADP3804 High Frequency Switch Mode Li-Ion Battery Charger; and the ADP3820 - 1% Precision, Single Cell Li-Ion Battery Charger.


ADI also manufactures GSM Power Controllers, which provide all of the power management functions required to properly power ADI's industry-leading GSM/GPRS chipsets. Examples of GSM power controllers from ADI are the ADP3404, the ADP3405, and the ADP3522.


Another group of power management IC's from Analog Devices are known as Microprocessor Supervisors and Reset Generators. These circuits monitor power supply voltage levels and code execution integrity in microprocessor-based systems. Aside from providing power-on reset signals, an on-chip watchdog timer can also reset the microprocessor if it fails to strobe within a preset timeout period. A reset signal can also be asserted by means of an external push-button, through a manual reset input. Examples of microprocessor supervisory IC's and reset generators are the ADM6316; the ADM823; and the ADM8617.


Aside from the above products, other power management IC's offered by ADI include: 1)  temperature sensors; 2) charge pumps for generating higher voltages from low voltage inputs, using capacitors as storage elements; 3) hot swap controllers for providing accurate inrush current control and protection against over-current events and voltage faults; 4) low dropout linear regulators; 5) dual MOSFET drivers for use in non-isolated synchronous buck power converters; 6) voltage sequencing and voltage tracking ICs for sequencing multiple power supplies; 7) switching regulators that operate in step up, step down, and inverting modes, and capable of generating a fixed or adjustable output voltage; and 8) hardware system monitoring IC's.


References:   www.maxim-ic.com;    www.atmel.com;    www.analog.com;




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