48V/12V Dual Battery Automotive Systems Require Bi-Directional DC/DC Controllers : Page 4 of 7

August 16, 2017 //By Bruce Haug, Linear Technology
48V/12V Dual Battery Automotive Systems Require Bi-Directional DC/DC Controllers
Fuel economy requirements and ADAS functions have led to the introduction of a 48V supply bus for cars that coexists with the traditional 12V rail. Both systems are interconnected through bi-directional DC/DC controllers. This article describes the requirements and considerations to optimize the interplay.

The LTC3871 is available in a thermally enhanced 48-lead LQFP package. Three temperature grades are available, with operation from –40°C to 125°C for the extended and industrial grades and a high temp automotive range of –40°C to 150°C. Figure 1 below shows its typical applications schematic. The P-Channel MOSFET shown at the top of the schematic is for over current and short circuit protection.

Integrated Start-Generator

The electronically controlled ISG replaces both the conventional starter and alternator with a single electric device for the following reasons:

  1. To eliminate the starter which is only a passive component during engine operation
  2. Replaces the present belt and pulley coupling between the alternator and the crankshaft
  3. To provide fast control of the generator voltage during load dumps
  4. To eliminate the slip rings and the brushes in some present wound rotor alternators
Design category: 

Vous êtes certain ?

Si vous désactivez les cookies, vous ne pouvez plus naviguer sur le site.

Vous allez être rediriger vers Google.