ZHCS520E May 1996 – May 2019 LM2586
PRODUCTION DATA.
Figure 20 shows the LM2586 used as a step-up (boost) regulator. This is a switching regulator that produces an output voltage greater than the input supply voltage.
A brief explanation of how the LM2586 boost regulator works is as follows (refer to Figure 20). When the NPN switch turns on, the inductor current ramps up at the rate of VIN/L, storing energy in the inductor. When the switch turns off, the lower end of the inductor flies above VIN, discharging its current through diode (D) into the output capacitor (COUT) at a rate of (VOUT − VIN)/L. Thus, energy stored in the inductor during the switch on time is transferred to the output during the switch off time. The output voltage is controlled by adjusting the peak switch current, as described in .
By adding a small number of external components (as shown in Figure 20), the LM2586 can be used to produce a regulated output voltage that is greater than the applied input voltage. The switching waveforms observed during the operation of this circuit are shown in Figure 21. Typical performance of this regulator is shown in Figure 22.