Issue link: https://resources.mouser.com/i/1442820
| 13 | The inductor is the energy storage device for all switching converters. The energy stored is calculated: E=½LI 2 (Joules)–I is the inductor current and L is the inductance. The variation of inductor current during the switcher operation is known as ripple current and its amplitude is determined by the value of inductance. Ripple current is usually kept below 30 percent of the output current in order to reduce AC and core losses. V l =di/dt–V l is the voltage across the inductor – di is the ripple current and dt is inversely proportional to the switching frequency. Key Inductor Specifications Key specifications for Bourns ® inductor products are I rms and I sat . I rms is the current that causes the inductor temperature to rise by 40˚C and I sat is the current that causes the inductance to decrease by 10-30 percent. The current in a switching converter is rarely stable, and the variation will be the result of transients, spikes, or sudden load and supply changes. The fall-off of inductance with increasing current is an important characteristic. Helping to remedy these issues is the Bourns ® Model PQ series, which is produced with ferrite and features an air gap. These features help keep the value inductance relatively stable with increasing current until the core saturates resulting in a sudden collapse of the inductance. Designed with a flat wire winding, the AEC-Q200 compliant Model PQ series inductors deliver a compact solution with exceptionally low DC and AC resistance and high saturation current handling of over 100 A. Figure 3: The model PQ series products offer a high operating temperature specified at 150˚C Sensing Voltage Measurement An important element of a micro hybrid DC/DC converter application design includes measurement of the sensing voltage (V sense ). Devices are used to sense input current continuously by measuring the voltage across a dedicated current sense resistor. Current sensing provides necessary precision channel-current balancing, and per-phase overcurrent protection. Current sense resistors are gaining in popularity due to their high measurement accuracy and relatively low cost compared to other technologies.