What is subharmonic oscillation?

Sub-harmonic oscillation is normally characterized by observing alternating wide and narrow pulses at the switch node. For peak current mode control, sub-harmonic oscillation occurs with a duty cycle greater than 50%.

What is valley current mode control?

DESCRIPTION. The A4403 is a buck converter that uses valley current-mode control. This control scheme allows very short switch on-times to be achieved, making it ideal for applications that require high switching frequencies combined with high input voltages and low output voltages.

Why is slope compensation needed?

As the boost inductor being designed is operating at constant frequency, slope compensation is required to ensure the stability of the converter.

What is voltage mode control?

Voltage mode control represents the most basic method, in which only the output voltage is returned through a feedback loop. The differential voltage, which is obtained to compare the output voltage with the reference voltage by an error amp, is compared with triangular waves by a PWM generator.

How do you make subharmonic?

The subharmonic is generated when two notes with the specific frequencies interact or periodically connect with one another. This means that subharmonics can be generated when the two notes are coming from the same source and place or as close as possible so that the listener perceives it as only one wave of sound.

How does buck converter increase current?

Fig. 2: The two operating states of a buck–boost converter: When the switch is turned on, the input voltage source supplies current to the inductor, and the capacitor supplies current to the resistor (output load). When the switch is opened, the inductor supplies current to the load via the diode D.

Does a buck converter regulate current?

Switching converters (such as buck converters) provide much greater power efficiency as DC-to-DC converters than linear regulators, which are simpler circuits that lower voltages by dissipating power as heat, but do not step up output current.

What is valley current limit?

Valley current limit keeps the on-time constant while only increasing the off-time so that the switching frequency decreases during current limit operation.

How is slope compensation calculated?

This downslope is calculated at: Slope = 0.5 × Vout/L. The maximum slope is Slopemax = 0.5 × Vout max/Lmin, which should be used in calculations.

How do you learn about subharmonic oscillations?

To learn about subharmonic oscillations, consider a buck circuit with peak current control, and how these oscillations may change based in relation to time and frequency. Figure 1 shows a buck circuit with peak current control that compares the error signal (VC) with the inductor current signal (IL).

Where do sub-harmonic oscillations in current-mode-controlled converters come from?

Sub-harmonic oscillations in current-mode-controlled converters are easily revealed through simple drawings as shown in akellyirl answer. However, it is less known that these oscillations find their origin in the inner current-loop instability affected by the presence of a right-half-plane zeros (RHPZ) pair.

What are harmonic oscillations?

Solutions that repeat with each cycle of the sound field are called harmonic oscillations, although they are in general nonlinear and contain higher harmonics of the driving frequency in their oscillation spectrum and thus also in their acoustic radiation spectrum.

How does a 3rd harmonic current phasor work?

Afterwards, the new 3rd harmonic current phasor is vectorially subtracted from an earlier stored average value. If the magnitude of obtained vector breaks the pre-defined limit, a trip signal is send to the operating relay. This HIFAS have to be installed in each CB, which makes the distribution system costlier.