|
Switch mode regulators4 V/ B! n: f& w' q
QCC3040 VFBGA contains two switch mode regulators for optimum power efficiency. These switch mode regulators5 |5 _/ r. R6 n: j2 g3 A, p: l
receive power from VBAT or VCHG under application software control.# c( ]4 T) ]! r/ Z- _+ _
The System SMPS generates the main 1.8 V supply rail, which supplies most of the analog circuits on QCC3040" E% s. `5 t( Z- n
VFBGA and the flash memory. The System SMPS can supply power to external components. L5 B0 d9 Y6 p0 t9 C ]* w8 Q
The digital SMPS generates the power for the digital circuits. It is variable voltage and automatically switches* J) s- A2 W% x# k+ `8 x
between 1.1 V (nominal) and 0.85 V (nominal) in low-power modes.- q/ k9 K; o- h( D" l; N7 q
The SMPS both have three operating modes:
- [$ ~3 T/ E6 K. V1 e* h1 Z■ Normal (PWM)
$ z4 A! G& O3 r, e■ Two low-power modes with reduced current capability:. l$ D* i c' X5 x: N
□ PFM
1 ^# P# J( ?6 X" ^□ ULP' n; d; n4 s2 Y2 L
Normally the system auto switches, but this is optionally disabled.8 ~) d2 B9 T$ G8 R; M
The SMPS uses a 4.7 μH inductor and a 4.7 μF output capacitor.9 D L' T$ M4 N8 j/ K% n9 ?
For guidance on choice of inductor, capacitor and layout, see QCC3040 VFBGA Hardware Design Guide (80-3 M6 X1 d1 D3 e" p% Q" @4 t+ h
CH285-1).# V! ^( M1 H* n/ X: H) {
A single node SMPS_DCPL is a low impedance decoupling point for the inputs to both SMPS. This point must have
+ U2 m0 I# [, \0 Ma 2.2 μF. QTIL recommends using a 100 nF capacitor on the SMPS_DCPL point. x. S) J7 k, z9 ~9 S! b# ]! I
The SMPS Regulators are enabled by a rising edge on SYS_CTRL, or a rising edge on VBAT or presence of VCHG.
- M$ a( V, y2 |+ |4 S# N4 r9 k/ G5 G4 E+ G3 a
|
|