POWER
of 5A when the input voltage is at 4.5V and the switching frequency is programmed to 2MHz
Stage shedding
2-phase boost converter. As load current decreases, so does the peak inductor current of each phase. When the peak current
reduces to the shedding threshold ISHED, DUAL of approximately 1.7A, Stage Shedding activates where the device operates as a single-phase boost converter instead of a 2-phase. In this mode of operation, the second phase is turned off and the peak inductor current limit of phase 1 is increased to ISHED, SINGLE, which is given by Equation 2.
As load is further reduced, this IC can be
programmed to operate in a low IQ current, frequency forced continuous mode (FCM) by Shedding feature is further detailed in Figure 2, which shows the behaviour of the inductor currents of each phase in both Burst Mode and FCM mode.
When the SYNC/MODE pin is connected to signal ground (SGND), the IC operates in Burst Mode where the output regulation voltage is maintained by reducing the switching
current with peak I programmed using follow the pulse allowing for only 15μA of quiescent current when there is no load at the output.
operates in FCM at light loads. In this mode, the inductor current is allowed to go negative so the IC can switch at the programmed
for consistent and predictable switching harmonics and EMI, but at the cost of light FCM.
SSFM
For applications where EMI emissions are an additional resources to further reduce noise. SYNC/MODE pin and is compatible with Burst Mode and FCM operations. When SSFM is selected, the internal oscillator frequency is varied between the value programmed by the cent higher than that value. Figures 4 and 5 show the conducted and radiated EMI results
Conclusion
boost converter. Higher output power can be achieved using the 2-phase architecture and losses and enhance thermal performance all while keeping the overall footprint small despite requiring two inductors. Stage Shedding and Burst Mode operation further optional SSFM helps to reduce EMI emissions. output soft start and output overvoltage lockout, providing protection for downstream components from excessively high voltage. With its many features, this IC can be a great option for applications like handheld and industrial power supplies. Analog Devices
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NOVEMBER 2025 | ELECTRONICS FOR ENGINEERS 33
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