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
+−9 VD = ?LCR−+13.5 V

An ideal inverting buck-boost converter must produce −13.5 V from 9 V in continuous conduction. Find the duty cycle D.

Vin​ = 9 VVo​ = −13.5 V
D =
2.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 =
3.Medium
tiL​Imax​Imin​ΔI = ?DTT2T

An ideal boost converter turns 36 V into 120 V at 200 kHz with L = 330 µH. Find the peak-to-peak inductor ripple current ΔIL.

Vin​ = 36 VVo​ = 120 Vf = 200 kHzL = 330 µH
ΔIL = A
4.Medium
+−15 VSL = ?CR+−9 V

An ideal buck converter turns 15 V into 9 V at a switching frequency of 20 kHz. Find the inductance L that keeps the peak-to-peak inductor ripple current at 0.4 A.

Vin​ = 15 VVo​ = 9 Vf = 20 kHzΔIL = 0.4 A
L = µH
5.Hard
tiL​Imax​Io​DTT2T

A buck converter turns 15 V into 10.5 V at 200 kHz with L = 220 µH. Find the smallest load current Io,min for which it stays in continuous conduction.

Vin​ = 15 VVo​ = 10.5 Vf = 200 kHzL = 220 µH
Io,min = A
6.Hard
tiL​Imax​IL​DTT2T

An ideal inverting buck-boost converter turns 24 V into −72 V for a 20 Ω load at 20 kHz. Find the smallest inductance Lcrit for continuous conduction.

Vin​ = 24 VVo​ = −72 Vf = 20 kHzR = 20 Ω
Lcrit = µH

Answer key

  1. 1. D = 0.6
  2. 2. D = 0.4
  3. 3. ΔIL = 0.3818 A
  4. 4. L = 450 µH
  5. 5. Io,min = 0.0358 A
  6. 6. Lcrit = 31.25 µH

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