7660 Negative Voltage Converter

7660 Negative Voltage Converter

The 7660 is a negative voltage converter IC that converts positive voltage to negative voltage. Generating negative output from positive voltage is very easy using this chip. The circuit shown will convert a positive voltage in the range of +1.5 V to +10 V, into a corresponding negative voltage in the same range -1.5 V to -10 V.

The application for this chip is very simple and requires just two electrolytic capacitors of 10-µF value. The circuit is ideal if you need a negative DC voltage.

For example, if the supply voltage Vcc at Pin 8 was +5 V, then the corresponding output on Pin 5 will be -5 V.


Boost function

The boost function enables a higher switching frequency of the internal oscillator. It is optional and used on applications where noise is a major consideration of the design feature.

Many different manufacturers make this 7660 chip; however, the Intersil brand has a wider input voltage range +1.5 V to +12 V, whilst the rest operate between +1.5 V to +10 V. The Holtek and Intersil brands have a “BOOST” function on Pin 1 whilst on the rest this pin is not used.

Circuit

Positive to negative converter circuit.

Here is an example positive to negative converter circuit. It will work for any voltages between +1.5 V and +10 V, to produce a corresponding negative voltage.

These chips drive low current digital and analogue circuits that require a negative voltage rail.

The IC consumes a very low supply current of around 200 µA, and the power dissipation is typically around 1.4 W. The voltage conversion efficiency is around 97 %. As well as the standard DIP package, it is available in an SO-8 package.


Equivalent Chips

EquivalentName
LMC7660Switched Capacitor Voltage Converter
TC7660HHigh Frequency DC-DC Voltage Converter
HT7660CMOS Switched-Capacitor Voltage Converter
ICL7660SSuper Voltage Converter