TL3577 Datasheet, PDF (15/21 Pages) Texas Instruments – 100-kHz CURRENT-MODE SIMPLE STEP-UP/FLYBACK SWITCHING REGULATOR

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TL3577
100-kHz CURRENT-MODE SIMPLE STEP-UP/FLYBACK SWITCHING REGULATOR
SLVS633 – OCTOBER 2006
Table 2. Standardized Inductors and Manufacturer’s Part Numbers
Inductor Code
L47
L68
L100
L150
L220
L330
L470
L680
H150
H220
H330
H470
H680
H1000
H1500
H2200
AIE ⁽¹⁾
415 - 0932
415 - 0931
415 - 0930
415 - 0953
415 - 0922
415 - 0926
415 - 0927
415 - 0928
415 - 0936
430 - 0636
430 - 0635
430 - 0634
415 - 0935
415 - 0934
415 - 0933
415 - 0945
Manufacturer’s Part Number
Pulse ⁽²⁾
PE - 53112
PE - 92114
PE - 92108
PE - 53113
PE - 52626
PE - 52627
PE - 53114
PE - 52629
PE - 53115
PE - 53116
PE - 53117
PE - 53118
PE - 53119
PE - 53120
PE - 53121
PE - 53122
Renco ⁽³⁾
RL2442
RL2443
RL2444
RL1954
RL1953
RL1952
RL1951
RL1950
RL2445
RL2446
RL2447
RL1961
RL1960
RL1959
RL1958
RL2448
(1) AIE Magnetics, Div. Vernitron Corp., [phone] 2801 72nd Street North, St. Petersburg, FL 33710
(2) Pulse Engineering, [phone] 12220 World Trade Drive, San Diego, CA 92128
(3) Renco Electronics, Inc., [phone] 60 Jeffryn Blvd. East, Deer Park, NY 11729
3. Compensation Network (R_C, C_C) and Output Capacitor (C_OUT) Selection
The compensation network consists of resistor R_C and capacitor C_C, which form a simple pole-zero network and
stabilize the regulator. The values of R_C and C_C depend upon the voltage gain of the regulator, I_LOAD(max), the
inductor L, and output capacitance C_OUT. A procedure to calculate and select the values for R_C, C_C, and C_OUT
that ensures stability is described below. It should be noted, however, that this may not result in optimum
compensation. To guarantee optimum compensation, a standard procedure for testing loop stability is
recommended, such as measuring V_OUT transient responses to pulsing I_LOAD.
A. Calculate the maximum value for R_C.
R_C ≤ (750 × I_LOAD(max) × V_OUT2)/V_IN(min)2
Select a resistor less than or equal to this value, not to exceed 3 kΩ.
B. Calculate the minimum value for C_OUT using the following two equations.
C_OUT ≥ (0.19 × L × R_C × I_LOAD(max))/(V_IN(min) × V_OUT) and
C_OUT ≥ (V_IN(min) × R_C × (V_IN(min) + (3.74 × 10⁵ × L))/(487,800 × V_OUT3)
The larger of these two values is the minimum value that ensures stability.
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