Charge Pump Voltage Conversion with the Microchip TC7660SCOA713

Voltage conversion is a fundamental requirement in modern electronic design, where components often operate at different supply levels. While switch-mode power supplies (SMPS) are powerful, they can be overkill for simple polarity inversion or voltage doubling in low-power applications. For these scenarios, charge pump voltage converters offer a compelling alternative, providing a compact, inductor-less, and cost-effective solution. The Microchip TC7660SCOA713 stands as a quintessential example of this technology, delivering robust and efficient performance.

The TC7660SCOA713 is a monolithic, CMOS-based voltage converter IC. Its primary function is to convert a positive input voltage into a corresponding negative output (e.g., +5V to -5V), a process known as voltage inversion. Furthermore, it can be easily configured to achieve voltage doubling (e.g., +5V to +10V). The device operates on a simple yet elegant principle: the charge pump. It uses a network of external capacitors to "pump" and redistribute electrical charge, creating the desired output voltage without the need for magnetic components like inductors or transformers.

A key advantage of this architecture is its inherent simplicity. A basic negative voltage generator circuit requires only two external capacitors—a flying capacitor (`C1`) and an output reservoir capacitor (`C2`). This minimal component count translates into a remarkably small PCB footprint, low overall cost, and high reliability. The TC7660SCOA713 is designed to operate over a wide input voltage range, typically from 1.5V to 12V, making it versatile for various systems, from battery-powered devices with 3.3V or 5V rails to higher-voltage industrial applications.

The performance characteristics of this IC are notable. It features a low output impedance, typically around 50 ohms, which allows it to deliver output currents up to 20mA with minimal voltage drop. Its oscillator frequency runs at a nominal 10kHz, which can be boosted to 35kHz by connecting the OSC pin to ground, optimizing the design for either lowest power consumption or smallest capacitor size. High power efficiency, often exceeding 99%, is a hallmark of this design, as it primarily incurs losses due to internal MOSFET resistances rather than switching losses common in inductor-based systems.

Typical applications for the TC7660SCOA713 are numerous. It is perfectly suited for generating a negative bias voltage for operational amplifiers, sensors, and data acquisition systems in mixed-signal circuits. It is also widely used in portable and battery-operated equipment where space and weight are at a premium, and in interface circuits requiring a negative supply for RS-232 level shifting.

ICGOOODFIND: The Microchip TC7660SCOA713 is an exceptional choice for designers seeking a simple, efficient, and reliable solution for low-power voltage inversion and doubling. Its inductor-less design, minimal external component requirement, and wide operating range make it an indispensable tool for optimizing board space and BOM cost in a vast array of electronic applications.

Keywords: Charge Pump, Voltage Inversion, CMOS Voltage Converter, Low Power, Microchip TC7660