LM2576 Series Buck Regulator Design Procedure (Continued)
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FIGURE 7. LM2576(HV)-ADJ
PROCEDURE (Adjustable Output Voltage Versions)
Given: VOUT = Regulated Output Voltage VIN(Max) =
Maximum Input Voltage ILOAD(Max) = Maximum Load
Current F = Switching Frequency (Fixed at 52 kHz)
1. Programming Output Voltage (Selecting R1 and R2,
as shown in Figure 2) Use the following formula to select
the appropriate resistor values.
EXAMPLE (Adjustable Output Voltage Versions)
Given: VOUT = 10V VIN(Max) = 25V ILOAD(Max) = 3A F =
52 kHz
1. Programming Output Voltage (Selecting R1 and R2)
R1 can be between 1k and 5k. (For best temperature
coefficient and stability with time, use 1% metal film resis-
tors)
R2 = 1k (8.13 − 1) = 7.13k, closest 1% value is 7.15k
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