POWER
be completely prevented in a switch-mode power supply.
Load transients
The third influence on the accuracy of the generated voltage is the behaviour during load transients. If the load current changes, the voltage generated may deviate upward or downward. The higher the amplitude of the load transient and the faster it occurs, the greater the short-term deviation of the output voltage from the set point. To keep this influence on the error of the generated voltage as low as possible, the control loop speed must be fast. One tool that optimises a power converter circuit loop is LTpowerCAD from Analog Devices. Figure 2 shows the load transient of the LT8642S. The load current is increased from 100mA to 5A within 500ns and scorched again after 250µs. The voltage peak is about 27.5mV and the voltage dip is about 26.4mV. The measurement of the load transients was carried out with an LTpowerAnalyzer from Analog Devices. With this hardware, load transients can be measured easily for different current levels and with different transition times.
Figure 3 shows the different available
Figure 3. Different influences on the accuracy of the output voltage of a power supply.
influences on the tolerance of a switch- mode power supply.
When selecting a power supply circuit, it is essential to determine what voltage accuracy is required in an application. This is necessary to select the different components such as the power converter IC and resistor divider for DC
accuracy, as well as the coil and output capacitor for the output voltage ripple and the load transient influences. Finally, the control loop of the circuit is optimised to handle load transients as well as possible; for example, with the lowest possible voltage offset. For more information visit
www.analog.com
Get all the latest industry updates in the world of Electronics for Engineers, by reading EFE each month
E NGINEERS LECTRONICS FOR
Do you or a colleague need to receive a regular copy of Electronics For Engineers and the monthly newsletter?
DECEMBER/JANUARY 2026 | ELECTRONICS FOR ENGINEERS 13
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42
