Datasheet NCP1729 (ON Semiconductor) - 9

NCP1729
1 6 OSC −Vout Vin 2 5 + + + + + 3 4 Capacitors = 3.3 F
Figure 22. Negative Output Voltage Doubler
A single device can be used to construct a negative voltage doubler. The output voltage is approximately equal to −2.0 Vin minus the forward voltage drop of each external diode. The performance characteristics for the above converter are shown below. Note that curves A and C show the circuit performance with economical 1N4148 diodes, while curves B and D are with lower loss MBRA120E Schottky diodes. 0 TA = 25°C −2.0 A AGE (V) T
Curve V R
−4.0
in (V) All Diodes out ( )
B A 3.0 1N4148 118 −6.0 C B 3.0 MBRA120E 107 , OUTPUT VOL out −8.0 C 5.0 1N4148 91 V D D 5.0 MBRA120E 85 −10.0 0 10 20 30 40 Iout, OUTPUT CURRENT (mA)
Figure 23. Doubler Load Regulation, Output Voltage vs. Output Current http://onsemi.com 9