WM8310 datasheet(72/291 Pages) CIRRUS

72 / 291 page

WM8310

Pre-Production

PP, May 2012, Rev 3.1

The WM8310 can indicate the status of the Dynamic Voltage Scaling via a GPIO pin configured as a

“DC-DC1 DVS Done” or “DC-DC2 DVS Done” output (see Section 21). When a GPIO pin is

configured to indicate the DVS status, this signal is temporarily de-asserted during a DVS transition

on the associated DC-DC Converter, and is subsequently asserted to indicate the transition has

completed.

Note that the GPIO DVS outputs indicate the progress of all output voltage slews; they are not limited

to transitions associated with DCm_DVS_SRC; the GPIO DVS output also indicates the status of a

slew caused by a write to the DCm_ON_VSEL register, or a slew to the DCm_SLP_VSEL voltage.

Note also that the GPIO DVS outputs are indicators of the DVS control mechanism only; they do not

confirm the output voltage accuracy. The output voltage can be checked using the voltage status bits

if required (see Section 15.2).

15.7 DC-DC BOOST CONVERTER CONTROL

The DC-DC4 Boost Converter is designed as a power source for the Current Sinks described in

Section 16. The associated control registers for DC-DC4 are described in Section 15.4.2.

The Boost Converter uses one or other of the Current Sinks to provide voltage feedback in order to

control the converter output voltage. The selected Current Sink is determined by the DC4_FBSRC

the DC4_RANGE and DC4_FBSRC bits should be set according to whichever of the ISINKs requires

the higher supply voltage.

It is important to follow the recommended control sequences for switching on/off the Boost Converter

and Current Sinks. These sequences are described in Section 16.

The maximum current that can be supported by the Boost Converter varies with the output voltage, as

noted in the Electrical Characteristics (see Section 7.2).

The Current Sinks are suited to controlling LED backlight circuits. At low output voltages (eg. 5V), the

DC-DC4 boost converter is capable of supporting currents which exceed the maximum current rating

of the Current Sinks. Please contact Wolfson Applications support if further guidance is required on

configuring DC-DC4 for higher current than is supported by the Current Sinks.

15.8 LDO REGULATOR CONTROL

The LDO Regulators 1-10 can be configured to act as Current Limited Switches by setting the

LDOn_SWI field. When this bit is selected, there is no voltage regulation and the operating mode and

output voltage controls of the corresponding LDO are ignored. In Switch mode, the switch is enabled

(closed) and disabled (opened) by enabling or disabling the LDO.

Note that Switch mode cannot be selected via the OTP memory settings, and must be configured

after the WM8310 has entered the ON state.

When the LDO Regulator is disabled (and Switch mode is not selected), the output pin can be

configured to be floating or to be actively discharged. This is selected using LDOn_FLT.

15.9 HARDWARE CONTROL (GPIO)

The DC-DC Converters, LDO Regulators and EPE outputs may be controlled by the Hardware

Control inputs supported via the GPIO pins. The DCm_HWC_SRC, LDOn_HWC_SRC or

EPEn_HWC_SRC fields determine which of these Hardware Control inputs is effective.

See Section 21 for details of configuring the GPIO pins as Hardware Control inputs. Note that the

GPIO Hardware Control function is not the same as the GPIO Hardware Enable function.

Hardware Control is only possible when the applicable DCm_ENA, LDOn_ENA or EPEn_ENA control

bit is set (see Section 15.2), or if a Hardware Enable has been assigned to the relevant function and

is asserted.

The action taken in response to the selected Hardware Control inputs is configurable for each DC-DC

Converter, LDO Regulator or EPE output. The available options are described below.

WM8310 Datasheet(PDF) 72 Page - Cirrus Logic

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