LTC3588-2_10 Datasheet, PDF (14/18 Pages) Linear Technology – Piezoelectric Energy Harvesting Power Supply with 14V Minimum VIN

LTC3588-2
applications information
The frequency of the emission will be 120Hz for magnetic
ballasts but could be higher if the light uses electronic
ballast. The LTC3588-2 bridge rectifier can handle a wide
range of input frequencies.
Figure 9 shows the LTC3588-2 powered by a 48V com-
munications line. In this example, 1mA is the maximum
current that is allowed to be drawn. The 28k current limiting
resistor sets this current as the LTC3588-2 will shunt V_IN
at 20V. The advantage of this scheme is that the current at
the output is multiplied by the ratio of V_IN to V_OUT (less the
loss in the buck converter). This is useful in cases where
greater current is needed at the output than is available
at the input. The high UVLO of 16V prevents any start-up
issue as there is already a good multiplication factor at
that level. This same technique can be extended to AC
source that also have limited current available at the input.
28k
48V
1mA
1µF
6V
47µF
25V
4.7µF
6V
PZ1
PZ2
V_IN
PGOOD
LTC3588-2
CAP
SW
V_IN2
V_OUT
D1
D0
GND
PGOOD
22µH
V_OUT
3.45V
3.5mA
10µF ⁺
6V
LiFePO₄
35882 F09
Figure 9. Current Fed 3.45V LiFePO₄ Battery Charger
35882fa
14