BOOST-LP5569EVM: LP5569ARTWR

Hi Hyodo,

For Question 1:

When the charge-pump automatic-mode selection is enabled, voltage on the LED current LED sinks LED0 to LED8 are monitored. If the current sinks do not have enough headroom, the charge pump gain is set to 1.5* and remains in 1.5* mode until some condition occurs. 3.2V input voltage maybe high enough for your LEDs on, try to decrease the Vin(not low than 2.5V) and confirm the result.

For Question 2:

A 1uF capacitor is suggested to connected between PGND and VOUT. The charge-pump output capacitor is charged by the flying capacitor every switching cycle (1.25 MHz). This fast switching action requires that a low-inductance and low-resistance capacitor (ceramic) be used and that the output capacitor be connected to the LP5569 VOUT pin with a low-inductance connection. This is done by placing the output capacitor as close as possible to the VOUT and PGND pins of the LP5569 device, with connections on the same layer to avoid vias.

Best Regard

Monet Xu

Hi Monet,

Thank you for your early reply.

About Question 1 , I tried to decrease  the Vin(less 3.2V) , I confirmed 1.5x charge pump working.

Thank you.

But thereafter, I tried to increase Vin (~ 4.0 V), but it did not return from 1.5 x mode  to 1.0 x mode.

Once it went into 1.5 x mode, it did not return to 1.0 x mode with the LED on(auto mode).

Please let me know how to switch back to 1.0 x mode without LED off.

Best regards,

Hyodo

Hi Monet,

(from your answer.)

When the charge-pump automatic-mode selection is enabled, voltage on the LED current LED sinks LED0 to LED8 are monitored. If the current sinks do not have enough headroom, the charge pump gain is set to 1.5* and remains in 1.5* mode until some condition occurs. 3.2V input voltage maybe high enough for your LEDs on, try to decrease the Vin(not low than 2.5V) and confirm the result.

What conditions are “some condition occurs” in above your comment?

Could you please let me know the condition for transition from 1.5x to 1x when they set the auto mode?

Thanks

Hi Yusuke,

Under described condition, the charge pump gain is set to 1.5x and remains in 1.5x mode until one of the following occurs:

1. The LP5569 device enters the SHUTDOWN state and goes through the INITIAZATION or STARTUP state.
2. The charge pump mode is forced to 1X mode via the MISC register.
3. The LP5569 device entries power save when the charge pump is in automatic mode(CP_MODE_bits=3h)

In addition, charge pump return to 1x mode select can also be configurate by cp_return_1x bit in the MISC Register. When set cp_return_1x=1, charge pump mode is forced to 1x mode during shutdown or power save entry.

Best Reagrd

Monet Xu

Hi Monet-san

Regarding #3, 

3. The LP5569 device entries power save when the charge pump is in automatic mode(CP_MODE_bits=3h)

Customer found the issue that was not return from 1.5 x mode  to 1.0 x mode in Auto mode when they tried to increase Vin(~4.0V).

From your comment in the following E2E session

https://e2e.ti.com/support/power-management/f/power-management-forum/977392/lp5569-charge-pump-specification/3619758?tisearch=e2e-sitesearch&keymatch=LP5569#3619758

When setting the registers as the following:

cp_mode=11 ,cp_return_1x=1 ,powersave_en=1

If the VIN voltage drops once and the 1.5x mode is turned on and then the VIN voltage rises due to battery charging, charge pump will return to 1x mode while the LED is lighting.

Could you please let me know the condition that charge pump will return to 1x mode during Auto mode setting.

Also, could you please let me know the reason of customer verification results (not return to 1 x mode)?

Thanks

Muk

Hi Muk,

The comment in the attached E2E session maybe have some unreasonable. I will check on the EVM board and reply to you as quick as possible.

Best Regard

Monet Xu

do you have any update?

Hi Monet, could you help Yusuke-san in this case.

Monet-san,

Regarding 3. The LP5569 device entries power save when the charge pump is in automatic mode(CP_MODE_bits=3h)

In case of customer set CP_MODE_bits=3h, powersave_en=1, Charge pump will return to x1 mode when All LEDs  will be changed to inactive. Is it correct?

Could you please let me know the time between all LEDs turn off and the charge pump changed to x1 mode?

Thanks

Muk

hi Monet, please help to follow this case.

Hi Yusuke,

Yes, When the LED outputs are not active, the LP5569 device is able to enter the power-save mode automatically, thus lowering idle-current consumption down to 10 μA (typical).

The time between all LEDs turn off and charge pump changed to x1 mode is at the millisecond level, and We don‘t provide the precise spec.

Monet Xu

Monet-san,

Thank you for your answer.

Customer is considering the device control  method about transition from  x1.5 mode to x1.0 mode, if they cannot turn off LED.

From your comment,

1. The LP5569 device enters the SHUTDOWN state and goes through the INITIAZATION or STARTUP state.
2. The charge pump mode is forced to 1X mode via the MISC register.
3. The LP5569 device entries power save when the charge pump is in automatic mode(CP_MODE_bits=3h)

Customer will use #2 (forced to x1.0 mode)

(Procedure)

> Auto mode : x1.5 mode (Low Vin)

> Increased Vin : Customer detect the increasing voltage from system.

> They change the charge pump mode to x1.0 mode via the MISC register. (forced x1.0 mode)

> Wait time

> They change the charge pump mode from x1.0 mode to Automatic mode (Customer would like to use the auto mode, basically)

Is this procedure no problem?

Also, could you please your recommendation for wait time between x1.0 mode  and Automatic mode?

Thanks

Muk

hi Monet, please help to follow this case.