# What is hysteretic mode?

## What is hysteretic mode?

Hysteretic control means that the switching frequency is not fixed. The switching frequency can be calculated, but depends on the supply voltage, load voltage, and inductor value being used by the circuit.

What is current-mode converter?

A current-mode switching regulator is a sampled-data system, the bandwidth of which is limited by the switching frequency. Beyond half the switching frequency, the response of the inductor current to a change in control voltage is not accurately reproduced.

What is hysteresis control?

A hysteresis band is defined, and if the feedback signal is above that band, the plant is operated in one state; if it is below that band it is operated in the other state. If the feedback is within the band, the operating state is left unchanged. Hysteresis control is widely employed.

### How does current-mode control work?

Current-mode control addresses the slow response of voltage-mode control because the inductor current rises with a slope determined by the difference between the input and output voltages and hence responds immediately to line- or load-voltage changes.

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.

What is PWM current control?

A switch-mode converter varies its dc output current in response to load changes. One widely-used approach is pulse width modulation (PWM) that controls the power switch output power by varying its ON and OFF times. The ratio of ON time to the switching period time is the duty cycle.

#### Does PWM change voltage?

PWM does not change the value of voltage or current. It changes the amount of time a voltage is applied which effectively changes average power over time.

Why do we need ac voltage controller?

This varied voltage output is used for dimming street lights, varying heating temperatures in homes or industry, speed control of fans and winding machines and many other applications, in a similar fashion to an autotransformer. Voltage controller modules come under the purview of power electronics.

What is hysteresis force?

a retardation of the effect when the forces acting upon a body are changed (as if from viscosity or internal friction); esp: a lagging in the values of resulting magnetization in a magnetic material (as iron) due to a changing magnetizing force. – hys-ter-et-ic adj.