SPV1040 STMicroelectronics, SPV1040 Datasheet - Page 10

• Manufacturer Part Number: SPV1040
• Description: High efficiency solar battery charger with embedded MPPT
• Manufacturer: STMicroelectronics

Detailed description
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Detailed description
The SPV1040 is a monolithic, high efficiency, low voltage, self-powered DC-DC converter
that operates over a 0.3 V to 5.5 V DC input voltage range and provides a single output
voltage.
The device provides regulated output voltage and current by sensing the VCTRL feedback
of the external resistor divider and the voltage drop on the external sense resistor Rs,
respectively.
High efficiency is ensured by low power consumption in any working mode and by the
embedded Perturb & Observe MPPT algorithm.
The SPV1040 guarantees its own safety and application safety by stopping the N-channel
power switch in case of overcurrent or overtemperature conditions.
Soft-start mode
In order to guarantee powerup even when V
a proper startup strategy has been implemented.
Taking into account that the device is powered by the V
0.8 V, the device moves from power off to soft-start mode and the current flows from the
input to output through the intrinsic body diode of the synchronous rectifier. In this condition
V
Startup mode
When V
is not yet guaranteed. In such conditions, the N-channel power switch is forced ON with a
fixed duty cycle and the energy is transferred to the load via the intrinsic body diode of the P-
channel synchronous switch. If the shutdown overcurrent limit is exceeded, the power switch
is immediately turned OFF. The SPV1040 leaves Startup mode as soon as V
above 2 V.
MPPT mode
Once the device has exited Startup mode, the SPV1040 enters MPPT mode to search for
the maximum power point. The Perturb & Observe algorithm is based on monitoring either
the voltage or the current supplied by the DC power source unit so that the PWM signal duty
cycle is increased or decreased step by step according to the input power trend. Refer to
Figure
Constant voltage regulation
The constant voltage control loop consists of an internal voltage reference, an op amp and
an external resistor divider that senses the battery voltage and fixes the voltage regulation
set-point at the value specified by the user.
OUT
follows the LX voltage. The IC exits Startup mode when V
14, which illustrates the MPPT working principle.
OUT
goes above 0.8 V but it is still lower than 2 V, a proper biasing of both MOSFETs
Doc ID 18080 Rev 3
OUT
is very low (battery completely discharged),
OUT
voltage, If V
OUT
reaches 0.8 V.
OUT
is lower than
OUT
goes
SPV1040