PRD48BF480T400A00 Datasheet, PDF (18/22 Pages) Vicor Corporation – PRM™ Regulator

Not Recommended for New Designs
10.2.4 Midband Gain Design (R1,R3):
PRM48BF480T400A00
(Formerly VIP0001TFJ)
10.2.5 Compensation Zero Design (C1):
With reference to Figure 27: curve ABC is the:
 minimum output voltage in the application
 maximum input voltage expected in the application
 maximum load
PRM open loop response, and is where the maximum
crossover frequency occurs. In order for the maximum
crossover frequency to occur at the design choice F_CMAX,
the compensation gain must be equal and opposite of the
powertrain gain at this frequency. For stability purposes,
the compensation should be in the Mid-band (J-K) at the
crossover. Using Equation [1], the mid-band gain can be
selected appropriately.
With reference to Figure 27: curve EFG is the:
 maximum output voltage in the application
 minimum input voltage expected in the application
 minimum load in the application
PRM open loop response, and is where the minimum
crossover frequency F_CMIN occurs. Based on stability
criteria, the compensation must be in the mid-band at the
minimum crossover frequency, therefore F_CMIN will occur
where EFG is equal and opposite of G_MB. C1 can be
selected using Equation [2] so that F_Z1 occurs prior to
F_CMIN.
PRM^TM
Regulator
Figure 26 – Control circuit example
V•I CHIP CORP. (A VICOR COMPANY) 25 FRONTAGE RD. ANDOVER, MA 01810 800-735-6200
Rev. 1.2
07 / 2012
Page 18 of 22