L99LD21 datasheet(15/73 Pages) STMICROELECTRONICS

No. de pieza	L99LD21

Descripción Electrónicos	High power LED driver for automotive applications

PDF	73 Pages

Scroll/Zoom	100%

Fabricante Electrónico	STMICROELECTRONICS [STMicroelectronics]

Página de inicio	http://www.st.com

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15 / 73 page

DS11130 Rev 5

15/73

L99LD21

Boost controller

The effective switching frequency is doubled and the ripple cancellation effect results in a

reduction of the input and output current ripple. This allows small input and output

capacitances.

For an operation in dual-phase configuration, FB, COMP and SYNC_I/O pins must be

respectively connected together as shown in Figure 5.

Figure 5. Pin connections in dual-phase boost controller

One of the L99LD21 must be configured as the master and the other device must be

configured as the slave (see bit <1> on Table 15: CR#2: Control Register 2). The SYNC_I/O

of the master acts as an output, whilst the slave one respectively as an input. The master

boost provides a clock signal to the slave, in order to achieve an interleaved switching

activity of the slave boost controller, which is 180° out of phase to that of the master.

For a proper current balancing between the boost phases, the shunt resistors, which are

placed in series to the source of the mosfets, and the inductors, must be identical.

L99LD21 Datasheet(PDF) 15 Page - STMicroelectronics