MB39C831 Datasheet, PDF (11/40 Pages) Cypress Semiconductor – Ultra Low Voltage Boost Power Management IC for Solar/Thermal Energy Harvesting Datasheet

MB39C831
Charge Mode: MPPT_ENA = H, ENA = H
In order to operate the charge mode, it supposes that to connect lithium ion secondary batteries, and so on, to VCC pin. See
Figure 11-2 circuit to use the charge mode.
The charge mode is necessary to set MPPT_ENA = H and ENA = H. Both MPPT_ENA and ENA are connected to the VCC
pin, and a Li-ion battery should be connected to the VOUT pin to make the VOUT ≥ 2.6V (upper threshold of VOUT detection
voltage 2: VOUTDETH2). See Figure 10-2 Start-up/shut-down sequences of charge mode.
Figure 7-2 Start-up/Shut-down Sequences of Charge Mode (MPPT_ENA = H, ENA=H)
Release Voltage
0.35V
VDD Voltage _0V
0.2V
0V
VST
startup voltage _0V
2.6V
VCC Voltage
0V
VOUT=Li-ion Voltage(>=2.6V)
VOUT Voltage
0V
VCC=VOUT
4V VCC=VOUT
3.7V
4V
3.7V
Battery Charging Operation
2.55V
0V
2.55V
VOUT=Li-ion Voltage(>=2.55V)
0V
LX
switching
VCC-VOUT
SW1
OFF
ON
CSH1
VCC/2
0V
CSH2
VCC/2
0V
DET1
0V
OFF
0V
0V
Same as VCC Voltage
0V
DET0
0V
U
S R M RM
[1]
[2]
[3],[4]
0V
M RM
[5]
U
U
[6]
Mark
U
S
R
M
State
UVLO
Start-Up
Release Voltage
MPPT Charge
[1] When 0.35V (Minimum input voltage at start-up: VSTART) or higher voltage is applied to the VDD pin, the start-up circuit
activates charging the VCC capacitor C2 (see Figure 3-1).
[2] When the VCC reaches 2.6V (upper threshold of VCC detection voltage 2: VCCDETH2) and the VOUT is higher than 2.6V
(upper threshold of VOUT detection voltage 2: VOUTDETH2), the operation of the start-up circuit stops and the internal switch
SW1 (see Figure 3-1) between VCC and VOUT is turned on. Then the DC/DC converter activates charging the Li-ion battery
(see Figure 3-1), and the MPPT control starts at the same time.
[3] While the DC/DC converter is continuously operated, the voltage of VDD is controlled to the MPPT value setting by S0, S1,
and S2 pins. (For more detail, refer to Chapter 7.3).
[4] When the voltage of the Li-ion battery reaches 4V (upper threshold of VOUT detection voltage 3: VOUTDETH3), the
charging of the Li-ion battery stops. When the voltage of the Li-ion battery drops and reaches 3.7V (lower threshold of VOUT
detection voltage 3: VOUTDETL3), the charging of the Li-ion battery starts again.
[5] When the VDD voltage drops and reaches 0.2V (lower threshold of UVLO detection voltage: VUVLOL), the operation of the
DC/DC converter stops, and then the voltage of the VOUT and VCC starts to decreases.
Document Number: 002-08404 Rev *A
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