FEDL9077-02

Issue Date: Feb.20, 2013

ML9077

Power-saving solar power supply control LSI

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GENERAL DESCRIPTION

ML9077 controls charging a solar power current to a rechargeable battery.

The control circuit is consists of a overcharge prevention circuit, a charge control circuit and a rechargeable battery voltage

monitor circuit. Each circuit performs following operation.

● Overcharge prevention circuit

When a rechargeable battery becomes FULL charge state, the current of solar cell is drawn to VSS and the charge

current for the rechargeable battery is omitted so that rechargeable battery voltage does not rise any more.

● Charge control circuit

The voltage of solar cell (VSC) is always compared to the voltage of rechargeable battery (VBAT) and it

will have starting to charge the battery if VSC＞VBAT, and stop to charge if VSC≦BAT.

● Rechargeable battery voltage monitor circuit（BOD : Brown-Out Detector）

The voltage of rechargeable battery (VBAT) is always supervised, and it controls VBAT low voltage detection signal

(VBOD) and rechargeable battery voltage output (VDO).

FEATURES

• Self control the solar cell current for charging a rechargeable battery.

• Direct charge solar cell current (ISC) to a rechargeable battery.

− [VSC＞2.0V, ISC≦1mA conditions]: Potential difference=Max 0.1V （VSC-VBAT）

− [VSC＞2.0V, ISC≦1mA conditions]: Potential difference=Max 2.0V （VSC-VBAT）

• 2 Selectable overcharge prevention voltage.

• 2 Selectable low voltage detection voltage.

• Power supply system detects a low voltage of rechargeable battery and power off a external microcomputer.

• Low power operation

− Solar cell current : 80nA

− Rechargeable battery current : 80nA

• Shipment

− 12-pin plastic WQFN

Part number: ML9077GDZ05B

− Chip

Part number: ML9077WA

• Guaranteed operating range

− Operating temperature: −20°C to 70°C

− Operating voltage: V