DC-DC converters worksheet with answers

Free printable DC-DC converters worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
+−48 VD = ?LCR+−19.2 V

An ideal buck converter must produce 19.2 V from 48 V in continuous conduction. Find the duty cycle D.

Vin​ = 48 VVo​ = 19.2 V
D =
2.Easy
+−36 VD = ?LCR−+144 V

An ideal inverting buck-boost converter must produce −144 V from 36 V in continuous conduction. Find the duty cycle D.

Vin​ = 36 VVo​ = −144 V
D =
3.Medium
+−24 VLSCR = 20 Ω+−32 V

An ideal boost converter turns 24 V into 32 V for a 20 Ω load. Find the average inductor current IL.

Vin​ = 24 VVo​ = 32 VR = 20 Ω
IL = A
4.Medium
tiL​Imax​Imin​ΔI = ?DTT2T

An ideal inverting buck-boost converter turns 36 V into −84 V at 200 kHz with L = 150 µH. Find the peak-to-peak inductor ripple current ΔIL.

Vin​ = 36 VVo​ = −84 Vf = 200 kHzL = 150 µH
ΔIL = A
5.Hard
tiL​Imax​IL​DTT2T

An ideal boost converter turns 15 V into 30 V for an 8 Ω load at 250 kHz. Find the smallest inductance Lcrit for continuous conduction.

Vin​ = 15 VVo​ = 30 Vf = 250 kHzR = 8 Ω
Lcrit = µH
6.Hard
+−15 VSL = 100 µHC = ?R+−7.5 V

A buck converter turns 15 V into 7.5 V at 100 kHz with L = 100 µH. Find the output capacitance C that limits the peak-to-peak output ripple to 20 mV.

Vin​ = 15 VVo​ = 7.5 Vf = 100 kHzL = 100 µHΔVo = 20 mV
C = µF

Answer key

  1. 1. D = 0.4
  2. 2. D = 0.8
  3. 3. IL = 2.133 A
  4. 4. ΔIL = 0.84 A
  5. 5. Lcrit = 2 µH
  6. 6. C = 23.44 µF

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