ZHCSH35B November 2017 – May 2021 LM73605-Q1 , LM73606-Q1
PRODUCTION DATA
In CCM operation, inductor current has a continuous triangular waveform. The HS switch is on at the beginning of a switching cycle and the LS switch is turned off the end of each switching cycle. In auto mode, the LM73605-Q1/6-Q1 in CCM when the load current is higher than ½ of the peak-to-peak inductor current (ILripple). In FPWM mode, the LM73605-Q1/6-Q1 in CCM, regardless of load.
In CCM operation, the switching frequency is typically constant, unless tON-MIN, tOFF-MIN, or IPEAK-MIN conditions are met. The constant switching frequency is determined by RT pin setting, or the external synchronization clock frequency. The duty cycle is also constant in CCM: D = VOUT / VIN if loss is ignored, regardless of load. The peak-to-peak inductor ripple is constant with the same VIN and VOUT, regardless of load.
With very high or very low supply voltages, when the tON-MIN or tOFF-MIN condition is met, the frequency reduces to maintain VOUT regulation with even higher or lower VIN, respectively. When the IPEAK_MIN condition is met in auto mode, the switching frequency folds back to provide higher efficiency. IPEAK_MIN is disabled in FPWM mode.