ZHCSHY8 March 2018 LP87561-Q1 , LP87562-Q1 , LP87563-Q1 , LP87564-Q1 , LP87565-Q1
PRODUCTION DATA.
The LP8756x-Q1 device supports start-up and shutdown sequencing with programmable delays for different regulator outputs using one EN1, EN2, EN3 control signal. The regulator is selected for delayed control with:
There are four time steps available for start-up and shutdown sequences. The delay times are selected with DOUBLE_DELAY bit in CONFIG register and HALF_DELAY bit in PGOOD_CTRL2 register as shown in Table 4.
X_STARTUP_DELAY or
X_SHUTDOWN_DELAY |
DOUBLE_DELAY = 0h
HALF_DELAY = 1h |
DOUBLE_DELAY = 1h
HALF_DELAY = 1h |
DOUBLE_DELAY = 0h
HALF_DELAY = 0h |
DOUBLE_DELAY = 1h
HALF_DELAY = 0h |
---|---|---|---|---|
0h | 0 ms | 0 ms | 0 ms | 0 ms |
1h | 0.32 ms | 0.64 ms | 1 ms | 2 ms |
2h | 0.64 ms | 1.28 ms | 2 ms | 4 ms |
3h | 0.96 ms | 1.92 ms | 3 ms | 6 ms |
4h | 1.28 ms | 2.56 ms | 4 ms | 8 ms |
5h | 1.6 ms | 3.2 ms | 5 ms | 10 ms |
6h | 1.92 ms | 3.84 ms | 6 ms | 12 ms |
7h | 2.24 ms | 4.48 ms | 7 ms | 14 ms |
8h | 2.56 ms | 5.12 ms | 8 ms | 16 ms |
9h | 2.88 ms | 5.76 ms | 9 ms | 18 ms |
Ah | 3.2 ms | 6.4 ms | 10 ms | 20 ms |
Bh | 3.52 ms | 7.04 ms | 11 ms | 22 ms |
Ch | 3.84 ms | 7.68 ms | 12 ms | 24 ms |
dh | 4.16 ms | 8.32 ms | 13 ms | 26 ms |
Eh | 4.48 ms | 8.96 ms | 14 ms | 28 ms |
Fh | 4.8 ms | 9.6 ms | 15 ms | 30 ms |
An example of start-up and shutdown sequences is shown in Figure 16 and Figure 17. The start-up and shutdown delays for the BUCK0, BUCK1 regulators are 1 ms and 4 ms and for the BUCK2, BUCK3 regulators 3 ms and 1 ms. The delay settings are used only for enable/disable control with EN1, EN2, EN3 signals, not for Roof/Floor control.