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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Name: ____________________   Date: ____________

1.Easy
+−48 VLD = ?CR+−80 V

An ideal boost converter must produce 80 V from 48 V in continuous conduction. Find the duty cycle D.

Vin​ = 48 VVo​ = 80 V
D =
2.Easy
+−15 VSLCR−+10 V

An ideal buck-boost converter turns 15 V into 10 V and delivers 1.5 A to its load. Find the average input current Iin.

Vin​ = 15 VVo​ = 10 VIo = 1.5 A
Iin = A
3.Medium
tiL​Imax​Imin​ΔI = ?DTT2T

An ideal buck converter turns 36 V into 14.4 V at 50 kHz with L = 100 µH. Find the peak-to-peak inductor ripple current ΔIL.

Vin​ = 36 VVo​ = 14.4 Vf = 50 kHzL = 100 µH
ΔIL = A
4.Medium
tiL​Imax​Imin​ΔI = ?DTT2T

An ideal buck converter turns 36 V into 18 V at 25 kHz with L = 220 µH. Find the peak-to-peak inductor ripple current ΔIL.

Vin​ = 36 VVo​ = 18 Vf = 25 kHzL = 220 µH
ΔIL = A
5.Hard
tvo​Vo​ΔV = ?DTT2T

A buck converter turns 24 V into 18 V for a 20 Ω load at 250 kHz, with L = 22 µH and C = 100 µF. Find the peak-to-peak output voltage ripple ΔVo in mV.

Vin​ = 24 VVo​ = 18 Vf = 250 kHzL = 22 µHC = 100 µF
ΔVo = mV
6.Hard
tiL​Imax​IL​DTT2T

An ideal buck converter turns 9 V into 6.3 V for a 4 Ω load at 25 kHz. Find the smallest inductance Lcrit for continuous conduction.

Vin​ = 9 VVo​ = 6.3 Vf = 25 kHzR = 4 Ω
Lcrit = µH

Answer key

  1. 1. D = 0.4
  2. 2. Iin = 1 A
  3. 3. ΔIL = 1.728 A
  4. 4. ΔIL = 1.636 A
  5. 5. ΔVo = 4.091 mV
  6. 6. Lcrit = 24 µH

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