Hello,
The datasheet says
The MP1542 is a current mode step up converter with a 2A, 0.18Ω internal switch to provide a highly efficient regulator with fast response.
Would it correct to assume that the IC can handle 2A continuous current, transients or just the capability of the MOSFETs to switch large current. The Web Designer tool spits out an error when setting Iout to 2A, the max current 600mA.
The 2A figure refers to a maximum switch current, which differs from maximum continuous output current due to the need to accommodate ripple in the switching waveform, among other factors.
Thank you Rick.
So what does it mean to have switch current at that rating and limited continuous current ?
The MP1542 is a component product, not a complete functional system; the capabilities of a circuit built using it will be dependent on choices made by the circuit designer, which are beyond the control of the component manufacturer.
The 2A switch rating reflects information that the manufacturer actually has control over. Prospective users are expected to use this information to calculate continuous output capacity for their specific implementation of the component, based on the additional design choices they make. Application information in the datasheet and various web tools such as the one mentioned are provided to assist users in this task.
When
Vin(min) = 5V
Vout = 12V
Efficiency (n) = 80%
fs = 1.3Mhz
Inductor = 4.7uf
Hence calculating the duty cycle using the below equation, i get 67%
and based on the graph Current Limit Vs Duty Cycle, the current limit based on the calculated duty cycle is around 3.35A. Correct me if am wrong, I presume the graph refers to the output current which does not meet for this application.
The chart above refers to the switch current limit as a function of duty cycle. As duty cycle increases, the switch spends more of its time in an “on” state, causing greater heat buildup in the device due to conduction losses. The switch current limit is lowered as duty cycle increases to accommodate this effect.