ME7660 Nanjing Micro One Electronics, ME7660 Datasheet

Page 1

... ME7660 Charge Pump DC-DC Voltage Converter Introduction Me7660 is a charge pump dc-to-dc voltage converter using AL-gate CMOS technology and optimization design. It converters a +1.5V to +10V input to a corresponding -1.5V to -10V output using only two external capacitors, eliminating inductors and their associated cost, size and EMI. The on-board oscillator operates at a nominal frequency of 10KHZ ...

Page 2

Pin Description Pin No. Symbol CAP 3 GND - 4 CAP 5 Vout 6 Low Voltage 7 OSC + 8 V Functional Block Diagram Description No connection Connecting external capacitor (+) pin Ground Pin Connecting external ...

Page 3

Absolute Maximum Rating ! Supply Voltage: +10. and OSC Inputs Voltage: -0. Current Into LV: 20µA 当 V+>3.5V 时 ! Output Short Duration (Vsupply ! Power Dissipation T Electrical Characteristics:(V Symbol Item + I Supply Current ...

Page 4

Typical Performance Characteristics Output Resistance vs.Supply Voltage 10000 1000 100 130 120 110 100 Supply Voltage (V) Output Load vs. Load Current ( Load Current(mA) 4(12) ME ...

Page 5

Output Voltage vs. Output Current ( Power Conversion Efficiency vs.Load Current (V 100 =+5V ...

Page 6

... Testing Circuit Detailed Description ME7660 together with two external capacitors C1 C2 complement a voltage Inverter. Capacitor C1 is charged to a voltage V switches S1 and S3 are closed ( while switches S2 and S4 are open during this half cycle); During the second half cycle of operation, switches S2 and S4 are closed, ...

Page 7

Theoretical Power Efficiency Considerations In theory, a capacitive charge pump can approach 100% efficiency if certain conditions are met: ! The drive circuitry consumes no power. ! The output switches have extremely low ON resistance and no offset when operation. ...

Page 8

... Paralleling Circuit ME7660 may be paralleled to reduce output resistance (see the figure below). Rout=Rout(of Me7660)/n(number of devices) Cascading Devices Me7660 may be cascaded as shown below to produce larger negative output voltage. However, due to the finite efficiency of each device, the number of practical cascading devices are limited. The output resistance is approximately single chip resistance ( n is the number of devices cascaded ...

Page 9

Adjusting Oscillator Frequency In some applications due to noise, it may be desirable to increase the oscillator frequency. This can be achieved by overdriving the oscillator from an external clock as shown in the figure below. The external clock output ...

Page 10

... So, the values of C1 and C2 should be increased by the same factor that the frequency has been reduced. Voltage Multiplication ME7660 may be applied to achieve positive voltage multiplication using the circuit shown in the figure below. 10(12) ME 7660 ...

Page 11

... Since the switches that allow the charge pumping operation are bi-directional, the charge transfer can be per-formed backwards as easily as forwards. Following figure shows ME7660 transforming – +5V (or +5V to +10V, etc.).The only problem here is that the internal clock and switch-drive section will not operate until some positive voltage has been generated ...

Page 12

Package Dimensions 12(12) ME 7660 ...