TDA4856 Datasheet, PDF (38/56 Pages) NXP Semiconductors – I2C-bus autosync deflection controller for PC monitors

Philips Semiconductors
I²C-bus autosync deflection controller for
PC monitors
Product specification
TDA4856
L4
S 8CH A 1AH A 00H A P
Soft-down sequence (XXXX XX00)
STDBY = 0
SOFTST = 0
Protection mode (XXXX XX00)
STDBY = 0
SOFTST = 0
registers are set
no
STDBY = 1?
yes
no
SOFTST = 1?
yes
L3 ⁽¹⁾
S 8CH A 1AH A 01H A P
Standby mode (XXXX XX01)
STDBY = 1
SOFTST = 0
all other register contents are random
(1) See Fig.18.
L2 ⁽¹⁾
MGL790
Fig.19 I²C-bus flow for protection and standby
mode.
Protection and standby mode
Soft-down sequence:
• Start the sequence by setting control bit SOFTST = 0
• BDRV duty cycle decreases
• HDRV duty cycle decreases.
Protection mode:
• Pins HDRV and BDRV are floating
• Continuous blanking at pin CLBL is active
• Pin HUNLOCK is floating
• PLL1 and PLL2 are disabled
• Register contents are kept in internal memory.
Protection mode can be left by 3 ways:
1. Entering standby mode by setting control
bit SOFTST = 0 and control bit STDBY = 1
2. Starting the soft-start sequence by setting control
bit SOFTST = 1 (bit STDBY = don’t care);
see L3 of Fig.18 for continuation
3. Decreasing the supply voltage below 8.1 V.
Standby mode:
• Set control bit STDBY = 1
• Driver outputs are floating (same as protection mode)
• Supply current is 9 mA
• Only the I²C-bus section and protection circuits are
operative
• Contents of all registers except the value of bit STDBY
and bit SOFTST are lost
• See L2 of Fig.18 for continuation.
1999 Jul 13
38