HA17431H Datasheet, PDF (10/15 Pages) Hitachi Semiconductor – Shunt Regulator

HA17431H Series
AC characteristic determination: This refers to the determination of the gain frequency characteristic of
the shunt regulator as an error amplifier. Taking the configuration in figure 2, the error amplifier
characteristic is as shown in figure 3.
G₁
f₁ f_AC
G_{2 When R5 ≠ 0}
When R₅ = 0
f₂
f_OSC Frequency f (Hz)
* f_OSC : PWM switching frequency
Figure 3 HA17431H Error Amplification Characteristic
In Figure 3, the following formulas are obtained:
Gain
G₁ = G₀ ≈ 50 dB to 60 dB (determined by shunt regulator)
G₂
=
R₅
R₃
Corner frequencies
f₁ = 1/(2π C₁ G₀ R₃)
f₂ = 1/(2π C₁ R₅)
G₀ is the shunt regulator open-loop gain; this is given by the reciprocal of the reference voltage fluctuation
∆Vref/∆V_KA, and is approximately 50 dB.
Rev.0, Sep. 2001, page 10 of 15