Cascading Devices

Cascading the LM2664s is an easy way to produce a greater

negative voltage (e.g. A two-stage cascade circuit is shown

in Figure 4).

If n is the integer representing the number of devices cas-

caded, the unloaded output voltage V

tive output resistance is equal to the weighted sum of each

individual device:

R

Note that, the number of n is practically limited since the in-

creasing of n significantly reduces the efficiency, and in-

creases the output resistance and output voltage ripple.

Combined Doubler and Inverter

In Figure 5, the LM2664 is used to provide a positive voltage

doubler and a negative voltage converter. Note that the total

current drawn from the two outputs should not exceed 50

mA.

DS100031-10

FIGURE 3. Lowering Output Resistance by Paralleling Devices

DS100031-11

FIGURE 4. Increasing Output Voltage by Cascading Devices

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