BUCK — Buck regulators

BUCK consists of two step-down buck regulators, BUCK1 and BUCK2.

BUCK has the following features:

Ultra-high efficiency (low IQ) and low noise operation
PWM and Hysteretic modes with automatic switching based on load
TWI configurable for forcing PWM mode to minimize output voltage ripple
Configurable output voltages between 1.0 V and 3.3 V

Hysteretic mode offers efficiency at lower load currents and typically operates up to half the maximum PWM current. PWM mode provides a clean supply operation due to a constant switching frequency, F_BUCK. This provides optimal coexistence with RF circuits. BUCK can automatically change between Hysteretic and PWM modes.

On/Off control

BUCK is enabled in the following ways.

VSET[n] pin
Control registers
GPIO[n] pin

The VSET1 and VSET2 pins are enabled only at power-on. If resistor R_VSETn is present, BUCK is enabled with the output voltage defined by the resistor value. If the pin is grounded, BUCK is disabled. See Default VOUT1 using an external resistor and Default VOUT2 using an external resistor.

Control registers BUCK1ENASET, BUCK1ENACLR, BUCK2ENASET, and BUCK2ENACLR have enable and disable bits for each BUCK. These registers override the default BUCK state.

A GPIO can be configured in register BUCKENCTRL to enable or disable BUCK.

If BUCK is disabled during power up, the system defaults to software control of BUCK.

Output voltage selection

The output voltage range for BUCK is programmable with TWI. The default output voltage selection is found on pins VSET1 and VSET2, which are configured using an external resistor to GND. The VOUT[n] pins have two voltage configuration registers that are selectable through a GPIO pin with predefined voltage settings available.

The VSET[n] pins are effective only at start up. The external resistor (maximum 5% tolerance) defines the default output voltage setting as found in the following table.

Table 1. Default VOUT1 using an external resistor
Symbol	Nominal resistance	VOUT1 start up output voltage
R_VSET1	<100 Ω (grounded)	0 V (OFF)
	4.7 kΩ	1.0 V
	10 kΩ	1.2 V
	22 kΩ	1.5 V
	47 kΩ	1.8 V
	68 kΩ	2.0 V
	100 kΩ	2.2 V
	150 kΩ	2.5 V
	250...500 kΩ	2.7 V

Table 2. Default VOUT2 using an external resistor
Symbol	Nominal resistance	VOUT2 start up output voltage
R_VSET2	<100 Ω (grounded)	0 V (OFF)
	4.7 kΩ	1.8 V
	10 kΩ	2.0 V
	22 kΩ	2.2 V
	47 kΩ	2.4 V
	68 kΩ	2.5 V
	100 kΩ	2.7 V
	150 kΩ	3.0 V
	250...500 kΩ	3.3 V

Note: To avoid issues with floating pins, make sure that the VSET[n]pins have the correct configuration.

The output voltage range is from 1.0 V to 3.3 V in 100 mV steps and is set in the voltage configuration registers BUCK1NORMVOUT and BUCK2NORMVOUT. Once the voltage is selected, register BUCKSWCTRLSEL must be written to for the values to take effect.

Registers BUCK1VOUTSTATUS and BUCK2VOUTSTATUS indicate the status or current voltage setting.

A GPIO can be configured to select between two voltage levels. The output voltage for retention mode is configured in registers BUCK1RETVOUT and BUCK2RETVOUT. Select a GPIO to control retention voltage in register BUCKVRETCTRL.

BUCK mode selection

BUCK operates in Automatic mode by default. When in Automatic mode, BUCK selects Hysteretic mode for low load currents, and PWM mode for high load currents.

In PWM mode, BUCK provides a clean supply operation due to constant switching frequency and lower voltage ripple for optimal coexistence with RF circuits.

Forced pulse width modulation (PWM) is set by the following:

Control register bits in BUCK[n]PWMSET
GPIO[n] pins in register BUCKPWMCTRL overriding the register setting for one or both BUCKs

Hysteretic mode can be forced in register BUCKCTRL0 for each BUCK. This setting is not available using GPIO.

Active output capacitor discharge

When the converter is disabled, active discharge can be enabled or disabled in register BUCKCTRL0 using R_DISCH from the output capacitors. The default setting is disabled.

Capacitor discharge is forced when there is a power cycle reset. See figure Power cycle.

Component selection

Recommended values for the inductor are shown in the following table.

Table 3. Recommended inductor specifications
Parameter	Value	Unit
Nominal inductance	2.2	μH
Inductor tolerance	≤ 20	%
DC resistance (DCR)	≤ 400	mΩ
Saturation current (I_sat)	> 350	mA
Rated current (I_max)	> 200	mA

Table 4. Recommended capacitor specifications
Parameter	Value	Unit
Nominal Capacitance	10	μF
Capacitor tolerance	≤ 20	%
Rated voltage	≥ 10	V
ESR	≤ 50	mΩ

Electrical specification

Table 5. BUCK electrical specification
Symbol	Description	Min.	Typ.	Max.	Unit
VOUT[n]_ACC	Output voltage accuracy	-5		+5	%
VSYS_MIN	Minimum VSYS voltage for enabling BUCK (dependent on POF setting)		2.7		V
I_OUT	Maximum BUCK current to maintain performance			200	mA
V_{DROP_OUT}	Drop-out voltage 1 mA load		100		mV
R_DISCH	Active output capacitor discharge resistance		2		kΩ
I_PWMTHRES	Load current threshold from Hysteretic to PWM mode (mode = AUTO)		90		mA
I_HYSTTHRES	Load current threshold from PWM to Hysteretic mode (mode = AUTO)		40		mA
VOUT_RIPPLEPWM	VOUT ripple in PWM mode I_OUT = 200 mA		5		mVpp
VOUT_RIPPLEHYST	VOUT ripple in Hysteretic mode		50		mVpp
EFF_BUCK	Efficiency in PWM mode VSYS = 3.8 V VOUT = 3.3 V I_OUT = 200 mA		93		%
f_BUCK	Switching frequency in PWM mode		3.6		MHz
t_STRT	Start-up time VOUT = 3.3 V C = 10 µF		1.2		ms
t_PWMMODE	Transition time Hysteretic to PWM mode Automatic (and via TWI or GPIO)		90 (55)		μs
t_HYST	Transition time Hysteretic to PWM mode Automatic (and through TWI or GPIO)		35 (25)		μs

Electrical characteristics

The following graphs show typical electrical characteristics for BUCK.

Figure 1. VBAT = 4.35 V: VOUT = 3.0 V vs. junction temperature

Figure 2. VBAT = 3.8: VOUT = 3.0 V vs. junction temperature

Figure 3. VBAT = 4.35 V: VOUT = 1.8 vs. junction temperature

Figure 4. VBAT = 3.8 V: VOUT = 1.8 vs. junction temperature

Figure 5. VBAT = 3.8 V: VOUT = 2.0 V: PFM frequency vs. current

Figure 6. VBAT = 3.8 V: VOUT = 2.0 V: GPIO BUCK start

Figure 7. VBAT = 3.8 V: VOUT = 2.0 V: GPIO PWM mode selection

Figure 8. VBAT = 3.8 V: VOUT = 2.0 V: GPIO PFM mode selection

Figure 9. VBAT = 3.8 V: VOUT = 2.0 V: Auto mode extreme load transient

Figure 10. VBAT = 3.8 V: VOUT = 2.0 V: PWM mode extreme load transient

Figure 11. VBAT = 3.8 V: VOUT = 2.0 V: VBUS detach

Figure 12. VOUT = 1.0 V: PWM Efficiency

Figure 13. VOUT = 1.8 V: PWM efficiency

Figure 14. VOUT = 2.1 V: PWM efficiency

Figure 15. VOUT = 3.3 V: PWM efficiency

Figure 16. VOUT = 1.0 V: Hysteretic efficiency

Figure 17. VOUT = 1.8 V: Hysteretic efficiency

Figure 18. VOUT = 2.1 V: Hysteretic efficiency

Figure 19. VOUT = 3.3 V: Hysteretic efficiency

Figure 20. VOUT = 1.8 V: FFT 10 mA: PFM

Figure 21. VOUT = 1.8 V: FFT 50 mA: PFM

Figure 22. VOUT = 1.8 V: FFT 100 mA: PWM: clock = 3.8 MHz

Figure 23. VOUT = 1.8 V: FFT 200 mA: PWM: clock = 3.8 MHz

Figure 24. BUCK dropout

Registers

Instances

Instance	Base address	Description
BUCK	0x00000400	BUCK registers BUCK register

Instance

Base address

Description

BUCK

0x00000400

BUCK registers

BUCK register

Register overview

Register	Offset	Description
BUCK1ENASET	0x0	BUCK1 Enable pulse
BUCK1ENACLR	0x1	BUCK1 Disable pulse
BUCK2ENASET	0x2	BUCK2 Enable pulse
BUCK2ENACLR	0x3	BUCK2 Disable pulse
BUCK1PWMSET	0x4	BUCK1 PWM mode enable pulse
BUCK1PWMCLR	0x5	BUCK1 PWM mode disable pulse
BUCK2PWMSET	0x6	BUCK2 PWM mode enable pulse
BUCK2PWMCLR	0x7	BUCK2 PWM mode disable pulse
BUCK1NORMVOUT	0x8	BUCK1 Output voltage Normal mode
BUCK1RETVOUT	0x9	BUCK1 Output voltage Retention mode
BUCK2NORMVOUT	0xA	BUCK2 Output voltage Normal mode
BUCK2RETVOUT	0xB	BUCK2 Output voltage Retention mode
BUCKENCTRL	0xC	BUCK Enable GPIO Select
BUCKVRETCTRL	0xD	BUCK Retention Voltage select
BUCKPWMCTRL	0xE	BUCK Forced PWM mode GPIO select
BUCKSWCTRLSEL	0xF	BUCK Software Control select
BUCK1VOUTSTATUS	0x10	BUCK1 VOUT Status register. Lets software read the Vout value in case its driven by the FSM.
BUCK2VOUTSTATUS	0x11	BUCK2 VOUT Status register. Lets software read the Vout value in case its driven by the FSM.
BUCKCTRL0	0x15	BUCK Auto PFM to PWM Control select
BUCKSTATUS	0x34	BUCK status register

BUCK1ENASET

Address offset: 0x0

BUCK1 Enable pulse

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	W	TASKBUCK1ENASET			Request to enable BUCK1
			NOEFFECT	0	no effect
			SET	1	BUCK1 Enable request set

BUCK1ENACLR

Address offset: 0x1

BUCK1 Disable pulse

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	W	TASKBUCK1ENACLR			Request to disable BUCK1
			NOEFFECT	0	no effect
			SET	1	BUCK1 Enable request clr

BUCK2ENASET

Address offset: 0x2

BUCK2 Enable pulse

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	W	TASKBUCK2ENASET			Request to enable BUCK2
			NOEFFECT	0	no effect
			SET	1	BUCK2 Enable request set

BUCK2ENACLR

Address offset: 0x3

BUCK2 Disable pulse

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	W	TASKBUCK2ENACLR			Request to enable BUCK2
			NOEFFECT	0	no effect
			SET	1	BUCK2 Enable request clr

BUCK1PWMSET

Address offset: 0x4

BUCK1 PWM mode enable pulse

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	W	TASKBUCK1PWMSET			request for BUCK1 to enter forced PWM mode
			NOEFFECT	0	no effect
			SET	1	BUCK1 Forced PWM request

BUCK1PWMCLR

Address offset: 0x5

BUCK1 PWM mode disable pulse

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	W	TASKBUCK1PWMCLR			request for BUCK1 to leave forced PWM mode and return to Auto mode
			NOEFFECT	0	no effect
			SET	1	BUCK1 Auto mode request

BUCK2PWMSET

Address offset: 0x6

BUCK2 PWM mode enable pulse

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	W	TASKBUCK2PWMSET			request for BUCK2 to enter forced PWM mode
			NOEFFECT	0	no effect
			SET	1	BUCK2 Forced PWM request

BUCK2PWMCLR

Address offset: 0x7

BUCK2 PWM mode disable pulse

Bit number						7	6	5	4	3	2	1	0
ID													A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	W	TASKBUCK2PWMCLR			request for BUCK2 to leave forced PWM mode and return to Auto mode
			NOEFFECT	0	no effect
			SET	1	BUCK2 Auto mode request

BUCK1NORMVOUT

Address offset: 0x8

BUCK1 Output voltage Normal mode

Bit number						7	6	5	4	3	2	1	0
ID									A	A	A	A	A
Reset 0x02						0	0	0	0	0	0	1	0
ID	R/W	Field	Value ID	Value	Description
A	RW	BUCK1NORMVOUT			BUCK1 Output voltage Normal mode
			1V	0	1V
			1V1	1	1.1V
			1V2	2	1.2V(Default)
			1V3	3	1.3V
			1V4	4	1.4V
			1V5	5	1.5V
			1V6	6	1.6V
			1V7	7	1.7V
			1V8	8	1.8V
			1V9	9	1.9V
			2V0	10	2V
			2V1	11	2.1V
			2V2	12	2.2V
			2V3	13	2.3V
			2V4	14	2.4V
			2V5	15	2.5V
			2V6	16	2.6V
			2V7	17	2.7V
			2V8	18	2.8V
			2V9	19	2.9V
			3V0	20	3V
			3V1	21	3.1V
			3V2	22	3.2V
			3V3	23	3.3V
			3V30	24	3.3V

BUCK1RETVOUT

Address offset: 0x9

BUCK1 Output voltage Retention mode

Bit number						7	6	5	4	3	2	1	0
ID									A	A	A	A	A
Reset 0x02						0	0	0	0	0	0	1	0
ID	R/W	Field	Value ID	Value	Description
A	RW	BUCK1RETVOUT			BUCK1 Output voltage Retention mode
			1V	0	1V
			1V1	1	1.1V
			1V2	2	1.2V(Default)
			1V3	3	1.3V
			1V4	4	1.4V
			1V5	5	1.5V
			1V6	6	1.6V
			1V7	7	1.7V
			1V8	8	1.8V
			1V9	9	1.9V
			2V0	10	2V
			2V1	11	2.1V
			2V2	12	2.2V
			2V3	13	2.3V
			2V4	14	2.4V
			2V5	15	2.5V
			2V6	16	2.6V
			2V7	17	2.7V
			2V8	18	2.8V
			2V9	19	2.9V
			3V0	20	3V
			3V1	21	3.1V
			3V2	22	3.2V
			3V3	23	3.3V
			3V30	24	3.3V

BUCK2NORMVOUT

Address offset: 0xA

BUCK2 Output voltage Normal mode

Bit number						7	6	5	4	3	2	1	0
ID									A	A	A	A	A
Reset 0x08						0	0	0	0	1	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	BUCK2NORMVOUT			BUCK2 Output voltage Normal mode
			1V	0	1V
			1V1	1	1.1V
			1V2	2	1.2V
			1V3	3	1.3V
			1V4	4	1.4V
			1V5	5	1.5V
			1V6	6	1.6V
			1V7	7	1.7V
			1V8	8	1.8V(Default)
			1V9	9	1.9V
			2V0	10	2V
			2V1	11	2.1V
			2V2	12	2.2V
			2V3	13	2.3V
			2V4	14	2.4V
			2V5	15	2.5V
			2V6	16	2.6V
			2V7	17	2.7V
			2V8	18	2.8V
			2V9	19	2.9V
			3V0	20	3V
			3V1	21	3.1V
			3V2	22	3.2V
			3V3	23	3.3V
			3V30	24	3.3V

BUCK2RETVOUT

Address offset: 0xB

BUCK2 Output voltage Retention mode

Bit number						7	6	5	4	3	2	1	0
ID									A	A	A	A	A
Reset 0x08						0	0	0	0	1	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	BUCK2RETVOUT			BUCK2 Output voltage Retention mode
			1V	0	1V
			1V1	1	1.1V
			1V2	2	1.2V
			1V3	3	1.3V
			1V4	4	1.4V
			1V5	5	1.5V
			1V6	6	1.6V
			1V7	7	1.7V
			1V8	8	1.8V(Default)
			1V9	9	1.9V
			2V0	10	2V
			2V1	11	2.1V
			2V2	12	2.2V
			2V3	13	2.3V
			2V4	14	2.4V
			2V5	15	2.5V
			2V6	16	2.6V
			2V7	17	2.7V
			2V8	18	2.8V
			2V9	19	2.9V
			3V0	20	3V
			3V1	21	3.1V
			3V2	22	3.2V
			3V3	23	3.3V
			3V30	24	3.3V

BUCKENCTRL

Address offset: 0xC

BUCK Enable GPIO Select

Bit number						7	6	5	4	3	2	1	0
ID						D	C	B	B	B	A	A	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	BUCK1ENGPISEL			Select which GPI controls BUCK1_enable
			NOTUSED	0	Not used
			GPIO0	1	GPI_0 selected
			GPIO1	2	GPI_1 selected
			GPIO2	3	GPI_2 selected
			GPIO3	4	GPI_3 selected
			GPIO4	5	GPI_4 selected
			NOTUSED1	6	no GPI selected
			NOTUSED2	7	no GPI selected
B	RW	BUCK2ENGPISEL			Select which GPI controls BUCK2_enable
			NOTUSED1	0	Not used
			GPIO0	1	GPI_0 selected
			GPIO1	2	GPI_1 selected
			GPIO2	3	GPI_2 selected
			GPIO3	4	GPI_3 selected
			GPIO4	5	GPI_4 selected
			NOTUSED3	6	no GPI selected
			NOTUSED4	7	no GPI selected
C	RW	BUCK1ENGPIINV			Invert the sense of the selected GPIO
			NORMAL	0	not Inverted
			INVERTED	1	Inverted
D	RW	BUCK2ENGPIINV			Invert the sense of the selected GPIO
			NORMAL	0	not Inverted
			INVERTED	1	Inverted

BUCKVRETCTRL

Address offset: 0xD

BUCK Retention Voltage select

Bit number						7	6	5	4	3	2	1	0
ID						D	C	B	B	B	A	A	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	BUCK1VRETGPISEL			Select which GPI controls BUCK1_retention voltage sel
			NOTUSED	0	Not used
			GPIO0	1	GPI_0 selected
			GPIO1	2	GPI_1 selected
			GPIO2	3	GPI_2 selected
			GPIO3	4	GPI_3 selected
			GPIO4	5	GPI_4 selected
			NOTUSED2	6	Not used
			NOTUSED1	7	Not used
B	RW	BUCK2VRETGPISEL			Select which GPI controls BUCK2_retention voltage sel
			NOTUSED	0	Not used
			GPIO0	1	GPI_0 selected
			GPIO1	2	GPI_1 selected
			GPIO2	3	GPI_2 selected
			GPIO3	4	GPI_3 selected
			GPIO4	5	GPI_4 selected
			NOTUSED2	6	Not used
			NOTUSED1	7	Not used
C	RW	BUCK1VRETGPIINV			Invert the sense of the selected GPIO
			NORMAL	0	not Inverted
			INVERTED	1	Inverted
D	RW	BUCK2VRETGPIINV			Invert the sense of the selected GPIO
			NORMAL	0	not Inverted
			INVERTED	1	Inverted

BUCKPWMCTRL

Address offset: 0xE

BUCK Forced PWM mode GPIO select

Bit number						7	6	5	4	3	2	1	0
ID						D	C	B	B	B	A	A	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	BUCK1PWMGPISEL			Select which GPI controls BUCK1 force PWM
			NOTUSED1	0	Not used
			GPIO0	1	GPI_0 selected
			GPIO1	2	GPI_1 selected
			GPIO2	3	GPI_2 selected
			GPIO3	4	GPI_3 selected
			GPIO4	5	GPI_4 selected
			NOTUSED	6	Not used
			NOTUSED2	7	Not used
B	RW	BUCK2PWMGPISEL			Select which GPI controls BUCK2 force PWM
			NOTUSED1	0	Not used
			GPIO0	1	GPI_0 selected
			GPIO1	2	GPI_1 selected
			GPIO2	3	GPI_2 selected
			GPIO3	4	GPI_3 selected
			GPIO4	5	GPI_4 selected
			NOTUSED	6	Not used
			NOTUSED2	7	Not used
C	RW	BUCK1PWMGPIINV			Invert the sense of the selected GPIO
			NORMAL	0	not Inverted
			INVERTED	1	Inverted
D	RW	BUCK2PWMGPIINV			Invert the sense of the selected GPIO
			NORMAL	0	not Inverted
			INVERTED	1	Inverted

BUCKSWCTRLSEL

Address offset: 0xF

BUCK Software Control select

Bit number						7	6	5	4	3	2	1	0
ID												B	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	BUCK1SWCTRLSEL
			VSETANDSWCTRL	0	Allow VSET pins to set VOUT
			SWCTRL	1	Allow SW to override VSET pin
B	RW	BUCK2SWCTRLSEL
			VSETANDSWCTRL	0	Allow VSET pins to set VOUT
			SWCTRL	1	Allow SW to override VSET pin

BUCK1VOUTSTATUS

Address offset: 0x10

BUCK1 VOUT Status register. Lets software read the Vout value in case its driven by the FSM.

Bit number						7	6	5	4	3	2	1	0
ID									A	A	A	A	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	R	BUCK1VOUTSTATUS			BUCK1VoutStatus

BUCK2VOUTSTATUS

Address offset: 0x11

BUCK2 VOUT Status register. Lets software read the Vout value in case its driven by the FSM.

Bit number						7	6	5	4	3	2	1	0
ID									A	A	A	A	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	R	BUCK2VOUTSTATUS			BUCK2VoutStatus

BUCKCTRL0

Address offset: 0x15

BUCK Auto PFM to PWM Control select

Bit number						7	6	5	4	3	2	1	0
ID										D	C	B	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	RW	BUCK1AUTOCTRLSEL
			AUTO	0	Select Auto switching between PFM and PWM
			PFM	1	Select PFM mode only
B	RW	BUCK2AUTOCTRLSEL
			AUTO	0	Select Auto switching between PFM and PWM
			PFM	1	Select PFM mode only
C	RW	BUCK1ENPULLDOWN			BUCK1_EN_PULLDOWN
			LOW	0	BUCK1 Pull Down Disabled
			HIGH	1	BUCK1 Pull Down Enabled
D	RW	BUCK2ENPULLDOWN			BUCK2_EN_PULLDOWN
			LOW	0	BUCK2 Pull Down Disabled
			HIGH	1	BUCK2 Pull Down Enabled

BUCKSTATUS

Address offset: 0x34

BUCK status register

Bit number						7	6	5	4	3	2	1	0
ID						F	E	D	D	C	B	A	A
Reset 0x00						0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value	Description
A	R	BUCK1MODE			BUCK1Mode
			AUTOMODE	0	Auto mode
			PFMMODE	1	PFM mode
			PWMMODE	2	Force PWM mode
B	R	BUCK1PWRGOOD			BUCK1PwrGood
			BUCKDISABLED	0	BUCK powered off
			BUCKPOWERED	1	BUCK powered on
C	R	BUCK1PWMOK			BUCK1PwmOk
			PWMMODEDISABLED	0	PWM mode disabled
			PWMMODEENABLED	1	PWM mode enabled
D	R	BUCK2MODE			BUCK2Mode
			AUTOMODE	0	Auto mode
			PFMMODE	1	PFM mode
			PWMMODE	2	Force PWM mode
E	R	BUCK2PWRGOOD			BUCK2PwrGood
			BUCKDISABLED	0	BUCK powered off
			BUCKPOWERED	1	BUCK powered on
F	R	BUCK2PWMOK			BUCK2PwmOk
			PWMMODEDISABLED	0	PWM mode disabled
			PWMMODEENABLED	1	PWM mode enabled