L6730B datasheet(18/52 Pages) STMICROELECTRONICS

18 / 52 page

Device description

L6730 - L6730B

18/52

The L6730B can always sink current and so it can be used to supply the DDR Memory

termination BUS. If overcurrent is detected during the soft-start phase, the device provides

constant current-protection. In case there is short soft-start time and/or small inductor value

and/or high output capacitors value and thus, in case of high ripple current during the soft-start,

the converter can start-up in anyway and limit the current (Chapter 5.8: Monitoring and

protection on page 21) but not enter into HICCUP mode. The soft-start phase ends when VSS

reaches 3.5V. After that the over current-protection triggers the HICCUP mode (L6730). With

the L6730B there is the possibility to set the HICCUP mode or the constant current mode after

the soft-start acting on the multifunction pin CC/O/U. With the L6730 the low-side MOSFET(s)

management after soft-start phase depends on the S/O/U pin state (see related section). If the

sink mode is enabled the converter can sink current after soft-start (see Figure 10.) while, if the

sink mode is disabled the converter never sinks current (see Figure 11.).

Figure 10. Sink mode enabled: Inductor current during and after soft-start (L6730).

VOUT

VSS

VCC

L6730B 데이터시트(PDF) 18 Page - STMicroelectronics