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產品名稱：AXPM65611 200mA Triple DC-DC Converter with LDO AVDD for Powering AMOLED Displ
型號： AXPM65611
產片介紹：AXPM65611 is a triple DC-DC converter designed to drive AMOLED display panel requiring 3 supply rails It integrates an 200mA step-up converter VPOS, an 200mA inverting converter VNEG and an 20mA auxiliary LDO AVDD The device is particularly suitable for battery operated products, in which the major concern is the overall system efficiency

┄┄┄詳細介紹┄┄┄

Description

AXPM65611 is a triple DC-DC converter designed to drive AMOLED display panel requiring 3 supply

rails. It integrates an 200mA step-up converter VPOS, an 200mA inverting converter VNEG and an 20mA

auxiliary LDO AVDD. The device is particularly suitable for battery operated products, in which the major

concern is the overall system efficiency. The digital control allows programming the VNEG in digital steps.

Excellent line and load regulation, soft start with controlled inrush current limit, thermal shutdown and

short circuit protection are also integrated.

Features

? Operating input voltage range from 2.9V to 4.5V

? Step-up converter (VPOS)

– 4.6V output voltage

– 200mA output current

– 0.5% accuracy (25°C to 85°C)

? Inverting converter (VNEG)

– -1.4V to -4.4V programmable output voltage (-2.2V default)

– 200mA output current

? LDO (AVDD)

– 3.3V default or lower of Vin

– 20mA output current

? Efficiencies >90%

? Excellent line and load regulation

? Short circuit protection

? Thermal shutdown

Applications

? AMOLED power supply in portable devices like mobile phones, multi-media players, camcorders,

digital still cameras, and wearables.

1 Block Diagram and Application Circuit

2 Pin Description

2.1 Pin Names

2.2 Pin Functions

3 Electrical Specifications

3.1 Absolute Maximum Ratings

3.2 Thermal Data

3.3 ESD and Latch Up

3.4 Electrical Characteristics

http://www.melmedical.com.cn/uploadfile/2025/0219/20250219103948667.pdf

4 Functional Description

4.1 Overview

AXPM65611 is a high efficiency triple DC-DC converter consisting of 1 step-up converter,1

inverting converter and a AVDD LDO. The VPOS output is fixed at +4.6V and VNEG is

programmable via a digital interface in the range of -1.4V to -4.4V; with default at -2.2V. AVDD

is default set to 3.3V. The device has internal over-temperature protection, under voltage lockout

and soft start which guarantees proper operation during start-up。

4.2 Step-up Converter (VPOS)

Step-up converter 1 uses a fixed-frequency current-mode topology. Its output voltage (VPOS) is

programmed at the factory to 4.6V and cannot be changed by the user.

4.3 Inverting Converter (VNEG)

The inverting converter uses a constant-off-time current-mode topology. The converter's default

output voltage (VNEG) is -2.2V. It can be programmed from -1.4 V to -4.4V.

4.3.1 Programming VNEG

The digital interface allows programming of VNEG in discrete steps. If the output voltage

setting function is not required, then the CTRL pin can also be used as a standard enable

pin. The digital output voltage programming of VNEG is implemented using a simple digital

interface(SWIRE) with the timing shown in figure 4.

4.3.2 VNEG Transition Time

The transition time (t_SET) is the time required to move VNEG from one voltage level to the

next. The transition time is designed for typical 300µs.

4.4 LDO (AVDD)

AVDD is derived from a LDO and can be enabled through the EN pin by connecting to high. In

applications whereby the VIN pin falls below 3.3V, the AVDD output will follow the VIN input

voltage.

4.5 Soft Start and Start-up Sequence

AXPM65611 features a soft-start function to limit inrush current. LDO (AVDD) is enabled when

EN goes high. When CTRL goes high, step-up converter 1 starts with a reduced switch current

limit and 10ms later the inverting converter starts with its default value of -2.2V. The typical start

up sequence is shown in Figure 5. The 2 step-up converters operate independently and step-up

converter (VPOS) does not require LDO (AVDD) to be in regulation for it to start.

4.6 VPOS and VNEG Enable (CTRL)

The CTRL pin serves two functions: one is to enable and disable the device VPOS and VNEG,

and the other is to program the output voltage (VNEG) of the inverting buck-boost converter (see

Programming VNEG). If the VNEG programming function is not required, the CTRL pin can be

used as a standard enable pin for the device, which will start up with its default value of -2.2V on

VNEG.

The device is enabled when CTRL is pulled high and disabled when CTRL is pulled low. Note

that to ensure proper start up CTRL must be pulled low for a minimum of 200μs before being

pulled high again.

4.7 Under-voltage Lockout

The device features an under-voltage lockout function that disables it when the input supply

voltage is too low for proper operation.

4.8 Short Circuit Protection

4.8.1 Short Circuit During Operation

The device is protected against short circuit of VPOS and VNEG to ground and short circuit

of these two outputs to each other. During normal operation, an error condition is detected

if VPOS falls below 4.1V for longer than 3ms or VNEG is pulled above the programmed

nominal output by 500mV for longer than 3ms. In either case the device goes into shutdown

and the outputs are disconnected from the input. This state is latched, and to resume

normal operation, VIN must cycle below the under-voltage lockout threshold, or CTRL must

toggle LOW and then HIGH.

4.8.2 Short Circuit During Start-up

During start-up, an error condition is detected in the following cases:

• VPOS is not in regulation 10ms after CTRL goes HIGH.

• VNEG is higher than threshold level 10ms after CTRL goes HIGH.

• VNEG is not in regulation 20ms after CTRL goes HIGH.

If any of the above conditions is met the device goes into shutdown and the outputs are

disconnected from the input. This state is latched, and to resume normal operation, VIN

has to cycle below the undervoltage threshold, or CTRL has to toggle LOW and HIGH.

4.9 Output Discharge During Shut Down

The device outputs can be programmed for Discharge or HiZ during shutdown. Figure 6 shows

the shutdown output control. Device is default programmed for Discharge during shutdown.

4.10 Device Functional Modes

4.10.1 Operation with VIN < 2.9V

The recommended minimum input supply voltage for full performance is 2.9V. The device

continues to operate with input supply voltages below 2.9V but full performance is not

guaranteed. It does not operate with input supply voltages below the UVLO threshold.

4.10.2 Operation with VI ≈ VPOS (Diode Mode)

AXPM65611 features a "diode" mode that enables it to regulate its VPOS output even

when the input supply voltage is close to VPOS (that is, too high for normal step-up

operation). When operating in diode mode the VPOS boost converter's high-side switch

is disabled and its body diode used as the rectifier. Note that a minimum load of ≈2mA

is required to have proper output regulation in diode mode.

4.10.3 Operation with CTRL

When a low-level signal is applied to the CTRL pin the device is disabled and switching

is inhibited. When the input supply voltage is above the UVLO threshold and a high-level

signal is applied to the CTRL pin the device is enabled and its start-up sequence begins.

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