Integrated dual charge pump power supply and RS-232 transmitter/receiver

DETAILED DESCRIPTION We claim: 1.
An integrated single-chip voltage supply comprising: a means adapted to be connected to a supply voltage for charging a capacitor approximately to a supply voltage; a means for coupling said charged capacitor in series with said supply voltage to create a source of positive voltage approximately double the supply voltage; and a means for inverting said doubled voltage and making it available on the same chip, thereby providing a source of two available supply voltages on the same chip, one being a positive voltage approximately two times said supply voltage, and the other being a negative voltage approximately two times said supply voltage.
2.
The integrated single-chip voltage supply of claim 1 further characterized by said coupling means including a means for charging a second capacitor to approximately two times said supply voltage, and said inverting means including a means for inverting the positive doubled voltage on said second capacitor to provide an available negative voltage on the same chip in magnitude approximately twice said supply voltage.
3.
An integrated voltage supply and RS-232 transmitter circuit or the same semiconductor chip, comprising: an RS-232 transmitter circuit; a means adapted to be connected to a supply voltage for charging a capacitor approximately to a supply voltage; a means for coupling said charged capacitor in series with said supply voltage to create a source of positive voltage approximately double the supply voltage; a means for inverting said doubled voltage and making it available on the same chip, thereby providing a source of two available supply voltages on the same chip, one being a positive voltage approximately two times said supply voltage, and the other being a negative voltage approximately two times said supply voltage; and means connecting said doubled voltage and said inverted doubled voltage to said RS-232 transmitter circuit for powering said RS-232 transmitter circuit.
4.
The integrated single-chip voltage supply of claim 3 further characterized by said coupling means including a means for charging a second capacitor to approximately two times said supply voltage, and said inverting means including a means for inverting the positive doubled voltage on said second capacitor to provide an available negative voltage of magnitude approximately twice said supply voltage