The same circuit could for example be used to automatically film canister. (024007-1) Voltage Inverter with Cascade Stage 050 The circuit diagram shows a switched-capacitor voltage assists in inverting the input voltage. During the first clock inverter with +5-V input and 3-V output, along with a sup- phase it is charged to the input voltage, while during the sec- plementary cascade stage to generate a +17-V auxiliary volt- ond clock phase its positive terminal is connected to ground age. The capacitor connected to the CP and CP+ terminals while its other terminal is connected to the output. This gen- 88 Elektor Electronics 12/2002 SMALL CIRCUITSCOLLECTION erates a negative voltage at the output, with an amplitude C3 C5 C7 equal to the input voltage. Using the duty cycle, the IC 2µ2 16V 1µ 16V 1µ 16V described here generates a regulated output voltage of 3 V +5V D1 D2 D3 D4 D5 D6 +17V with a current capacity of 120 mA. 3mA The clocked operation makes it possible to connect an addi- C4 C6 C1 8 tional diode cascade stage for voltage multiplication. This con- VIN 1µ sists of a series of diodes (for instance, type SS24 SMD Schot- 2µ2 10V 1µ 16V 1 CP+ C2 tky diodes) with alternating pump and storage capacitors. The IC1 3V pump capacitors are connected to CP+ and charge when CP+ 2µ2 3 7 CP VOUT is at ground potential. When CP+ goes to a high-potential 120mA ADP3605 SHUTDOWN 4 SD level, the potentials on the upper plates of the pump capaci- tors are pushed up. Each pump capacitor then discharges into R1 VSENSE D1...D6 = SS24 C9 2 5 the following storage capacitor (connected to ground) via the 2µ2 intermediate diode. The voltage increases with each pump stage, resulting in a net voltage of around +17 V after three 024091 - 11 voltage boosts, with a maximum load capacity of 3 mA. The type ADP3605 IC is available from Analog Devices (www.analog.com/productSelection/pdf/ADP3605_a.pdf) and can be applied to the Shutdown input (SD) to disable the is housed in an SO8 SMD package. A High level (> +2.4 V) converter. (024091-1) 10k