The internal clock is also blocked, and the device skips some pulses. In sleep mode, it consumes very low quiescent current to further improve light-load efficiency. If the load is further decreased or there is no load that makes the inductor peak current below AAM peak current threshold set by the I 2C, the device enters sleep mode. If AAM mode is enabled with load decreasing, the device enters discontinuous conduction operation (DCM) with fixed-frequency as long as the inductor current approaches zero. Forced CCM can maintain a constant switching frequency and smaller output ripple, but it has low efficiency at light load. AAM (advanced asynchronous modulation) mode is employed to optimize the efficiency during light-load or no-load conditions. This device can operate in light load AAM or forced CCM mode. If in one PWM period, the current in the HS-FET does not reach the COMP set current value, the HS-FET remains on, saving a turn-off operation. In order to avoid shoot-through, dead time is inserted to avoid the HS-FET and LS-FET turning on at the same time. During this time, the inductor current flows through the LS-FET. When the HS-FET is off, the low-side switch (LS-FET) turns on immediately and remains on until the next clock starts. Both the feedback divider ratio and reference can be adjusted by the I 2C, which makes it easy to adjust for different output voltages. The higher the load current, the higher the COMP voltage will be. It determines how much energy should be transferred to the load. The output voltage of error amplifier depends on the difference of output feedback voltage and the internal high-precision reference. The HS-FET remains on until its current reaches the COMP voltage, which is the output of the internal error amplifier. Then the rising edge of the clock the high-side switch (HS-FET) turns on and the inductor current rises linearly to provide energy to the load. It is available with a wide 4.5V to 36V input supply range and can achieve up to 3A continuous output current with excellent load and line regulation over an ambient temperature range of -40☌ to +125☌.Īt moderate to high output currents, this device operates in a fixed-frequency, peak current control mode to regulate the output voltage. This device is a high-frequency, synchronous, step-down power supply.
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