SGM6230 Datasheet, PDF (11/14 Pages) SG Micro Corp – Step-Down Converter

SGM6230
2A, 38V, 385kHz Step-Down Converter
APPLICATION INFORMATION
To optimize the compensation components for conditions
not listed in Table2, the following procedure can be used.
1. Choose the compensation resistor (R3) to set the
desired crossover frequency. Determine the R3 value by
the following equation:
R3 
2π  C_OUT  f_C
G_EA  G_CS

V_OUT
V_FB
Where f_C is the desired crossover frequency (which
typically has a value no higher than 13kHz).
2. Choose the compensation capacitor (C3) to achieve
the desired phase margin. For applications with typical
inductor values, setting the compensation zero, f_Z1, below
one-forth of the crossover frequency provides sufficient
phase margin.
Determine the C3 value by the following equation:
C3

4
2π  R3  f_C
3. Determine if the second compensation capacitor (C6)
is required. It is required if the ESR zero of the output
capacitor is located at less than half of the 385kHz
switching frequency, or the following relationship is valid:
1
2π  C_OUT  R_ESR

f_S
2
Where, C_OUT is the output capacitance value, R_ESR is the
ESR value of the output capacitor, and f_S is the 385kHz
switching frequency. If this is the case, then add the
second compensation capacitor (C6) to set the pole f_P3 at
the location of the ESR zero. Determine the C6 value by
the equation:
C6

C_OUT  R_ESR
R3
Where, C_OUT is the output capacitance value, R_ESR is the
ESR value of the output capacitor, and R3 is the
compensation resistor.
Where, R3 is the compensation resistor value and f_C is
the desired crossover frequency, 13kHz.
SG Micro Corp
11
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