MC34166 ON Semiconductor, MC34166 Datasheet - Page 12

• Manufacturer Part Number: MC34166
• Description: (MC33166 / MC34166) Step-Up/Down/Inverting Switching Regulators
• Manufacturer: ON Semiconductor

T1 = Primary: Coilcraft M1496-A or General Magnetics Technology GMT−0223, 42 turns of #16 AWG on Magnetics Inc. 58350-A2 core.
T1 =
T1 = Secondary:
Heatsink = AAVID Engineering Inc. 5903B, or 5930B.
Multiple auxiliary outputs can easily be derived by winding secondaries on the main output inductor to form a transformer. The secondaries must
be connected so that the energy is delivered to the auxiliary outputs when the Switch Output turns off. During the OFF time, the voltage across
the primary winding is regulated by the feedback loop, yielding a constant Volts/Turn ratio. The number of turns for any given secondary voltage
can be calculated by the following equation:
Note that the 12 V winding is stacked on top of the 5.0 V output. This reduces the number of secondary turns and improves lead regulation. For
best auxiliary regulation, the auxiliary outputs should be less than 33% of the total output power.
Line Regulation
Load Regulation
Output Ripple
Short Circuit Current
Efficiency
Secondary: V
+
Tests
PWM
V
O2
O3
Oscillator
− 65 turns of #26 AWG
− 96 turns of #28 AWG
3
TOTAL
−12 V
−12 V
−12 V
−12 V
5.0 V
5.0 V
5.0 V
5.0 V
12 V
12 V
12 V
12 V
Thermal
V
V
V
V
V
V
V
in
in
in
in
in
in
in
= 15 V to 30 V, I
= 24 V, I
= 24 V, I
= 24 V, I
= 24 V, I
= 24 V, R
= 24 V, I
# TURNS (SEC) +
Figure 25. Triple Output Converter
S
R
5
Q
O1
O1
O1
O1
O1
MC34166, MC33166
L
+
= 0.1 W
= 2.0 A, I
= 500 mA to 2.0 A, I
= 2.0 A, I
= 2.0 A, I
= 2.0 A, I
http://onsemi.com
ILIMIT
O1
Reference
UVLO
0.1
= 2.0 A, I
O2
O2
O2
O2
V O(SEC) ) V F(SEC)
EA
12
Conditions
V O(PRI) )V F(PRI)
= 100 mA to 300 mA, I
= 300 mA, I
= 300 mA, I
= 300 mA, I
#TURNS (PRI)
O2
68 k
= 300 mA, I
O2
+
= 300 mA, I
O3
O3
O3
4
2
1
= 100 mA
= 30 mA to 100 mA
= 100 mA
+
24 V
V
in
1N5822
O3
1000
6.8 k
= 100 mA
O3
O3
= 100 mA
= 100 mA
1000
T1
+
MUR110
MUR110
5.05 V/2.0 A
V
O1
4.0 mV = ± 0.04%
450 mV = ±1.9%
350 mV = ±1.5%
2.0 mV = ± 0.02%
420 mV = ±1.7%
310 mV = ±1.3%
50 mV
25 mV
10 mV
4.3 A
1.83 A
1.47 A
83.3%
+
+
1000
1000
Results
pp
pp
pp
−12 V/100 mA
12 V/300 mA
V
V
O2
O3