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
+−12 VSLCR+−9 V

An ideal buck converter turns 12 V into 9 V and delivers 1.5 A to its load. Find the average input current Iin.

Vin​ = 12 VVo​ = 9 VIo = 1.5 A
Iin = A
2.Easy
+−12 VLD = 0.4CR+−Vo​ = ?

An ideal boost converter runs from 12 V with a duty cycle D = 0.4 in continuous conduction. Find the output voltage Vo.

Vin​ = 12 VD = 0.4
Vo = V
3.Medium
tiL​Imax​Imin​ΔI = ?DTT2T

An ideal inverting buck-boost converter turns 9 V into −21 V at 40 kHz with L = 220 µH. Find the peak-to-peak inductor ripple current ΔIL.

Vin​ = 9 VVo​ = −21 Vf = 40 kHzL = 220 µH
ΔIL = A
4.Medium
tiL​Imax​ = ?Imin​Io​DTT2T

A buck converter turns 15 V into 10.5 V for a 5 Ω load. It switches at 250 kHz with L = 100 µH. Find the peak inductor current Imax.

Vin​ = 15 VVo​ = 10.5 Vf = 250 kHzL = 100 µHR = 5 Ω
Imax = A
5.Hard
tiL​Imax​IL​DTT2T

An ideal inverting buck-boost converter turns 15 V into −45 V for a 5 Ω load at 50 kHz. Find the smallest inductance Lcrit for continuous conduction.

Vin​ = 15 VVo​ = −45 Vf = 50 kHzR = 5 Ω
Lcrit = µH
6.Hard
tvo​Vo​ΔV = ?DTT2T

A buck converter turns 48 V into 19.2 V for a 4 Ω load at 25 kHz, with L = 68 µH and C = 470 µF. Find the peak-to-peak output voltage ripple ΔVo in mV.

Vin​ = 48 VVo​ = 19.2 Vf = 25 kHzL = 68 µHC = 470 µF
ΔVo = mV

Answer key

  1. 1. Iin = 1.125 A
  2. 2. Vo = 20 V
  3. 3. ΔIL = 0.7159 A
  4. 4. Imax = 2.163 A
  5. 5. Lcrit = 3.125 µH
  6. 6. ΔVo = 72.09 mV

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