Detailed description

SPV1040

10/15

Doc ID 18080 Rev 3

6

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.

6.1

Soft-start mode

a proper startup strategy has been implemented.

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

6.2

Startup mode

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

above 2 V.

6.3

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 14, which illustrates the MPPT working principle.

6.4

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.