Datasheet

Time (s)
Discontinuous Conduction Mode (DCM)
I
Peak
Time (s)
Time (s)
Time (s)
Time (s)
Discontinuous Conduction Mode (DCM)
DCM - CCM Boundary
Continuous Conduction Mode (CCM)
Continuous Conduction Mode (CCM)
Switchnode Voltage Switchnode VoltageInductor CurrentInductor CurrentInductor Current
V
IN
I
AVERAGE
I
AVERAGE
V
IN
LM20123
SNVS524E –OCTOBER 2007–REVISED MARCH 2013 www.ti.com
Figure 24. Modes of Operation for LM20123
Design Guide
This section walks the designer through the steps necessary to select the external components to build a fully
functional power supply. As with any DC-DC converter numerous trade-offs are possible to optimize the design
for efficiency, size, or performance. These will be taken into account and highlighted throughout this discussion.
To facilitate component selection discussions the circuit shown in Figure 25 below may be used as a reference.
Unless otherwise indicated all formulas assume units of amps (A) for current, farads (F) for capacitance, henries
(H) for inductance and volts (V) for voltages.
12 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated
Product Folder Links: LM20123