HV9957K7-G Supertex, HV9957K7-G Datasheet

Page 1

... Supertex inc. Six-Channel LED Driver with Features Drives six strings of LEDs 30mA each X Phased PWM dimming X Pin-programmable dimming frequency or X synchronizable to an external signal PWM dimming to very low duty cycles X ±1.5% typical current and 0.5% duty cycle matching X Optional crystal oscillator for precision dimming ...

Page 2

... I Boost converter switch current SW C Loop compensation network COMP BCOM Boost converter operating mode Note: * Junction temperature internally linked. Supertex inc. 24-Lead QFN 0.50mm pitch HV9957K7-G Pin Configuration Value -0.3 to 6.5V 60V -0. +0.3V) DD 10mA -0. -65ºC to +150ºC Product Marking Package may or may not include the following marks ...

Page 3

... Average of all 6 channels DIM Pulse width matching Δt Deviation from avg of all 6 chs PW Refer to Output Pulse graph t Minimum sync pulse width SYNC(MIN) Internally generated dimming f frequency INT Supertex inc. (over recommended operating conditions at 25ºC unless otherwise specified) Min Typ + 7 1.0 ...

Page 4

... Logic low input current L I Logic high input current H Thermal (Guaranteed by design - not production tested.) Thermal resistance, junction to θ ambient j-a Thermal resistance, junction to θ underside plate j-p Supertex inc. (over recommended operating conditions at 25ºC unless otherwise specified) Min Typ Max - 48 540 600 - 35 - 160 4.00 4.20 4 ...

Page 5

... Normalization reference is the average current of all 6 channels at 900mV. Limits apply to each channel individually. Output Pulse (PWM Dimming) Abbreviations: OVP Over-Voltage Protection OCP Over-Current Protection OLP Open LED Protection SLP Shorted LED Protection OTP Over-Temperature Protection Supertex inc 20mA nominal range DO ref scale change 0.7 0.8 1.1 1.2 1.6 2.0 V (V) ...

Page 6

... PGND1-2 FBST V (ext) DVDD DD 4.75 - 5.25V DGND AVDD AGND FLT EN Host Controller DIM SYNC V DD DIM Xtal Supertex inc (56V max) BST C BST SW1-2 COMP SMPS FB Control Lowest V CH Temp Sensor Control Frequency Synthesizer FREF SFM x160 ...

Page 7

... LED strings. It gets its feedback from the active output channels, maintaining a minimum voltage of 900mV across the linear current regulators (CH1 - 6). Therefore, the boost converters’ output voltage (V Supertex inc. plus the maximum LED string voltage drop ( recommended that the boost ratio ( less. ...

Page 8

... ISET Enable The EN pin serves two functions: it enables and disables the HV9957, or resets fault circuitry. When held high for at Supertex inc. least 50ns the HV9957 is enabled. When toggled low for 10µs, the fault circuits are reset, except for OTP, which is self-resetting. ...

Page 9

... OVP is usually activated by an open or a partially open (Zener-protected) LED string as the boost converter seeks to regulate the voltage at output with the open LED. Supertex inc. The OVP pin goes into a high resistance state during shut- down to minimize supply current. Shorted LED Protection (SLP) Temperature Triggered Protection against shorted LED strings is provided ...

Page 10

... Toggling EN or cycling power resets the faulty strings. If the disabling of strings does not prevent die temperature Supertex inc. from rising, the second-stage OTP activates, shutting down the boost converter. OTP2 self-resets when die temperature falls by the hysteresis temperature, re-enabling the boost converter but not reconnecting faulty strings ...

Page 11

... Short string disabled Long string remains CH1 CH2 CH3 CH4 CH5 Supertex inc. Long String Favored Under-voltage Lock Out (UVLO) The boost converter and output drivers will not be enabled until V DD from the 4.2V turn-ON threshold, the boost converter and output drivers are disabled. ...

Page 12

... S/L indicates whether the farthest outlying channel is a short string or a long string (0=short, 1=long). ACH is all channels high - when all channels are above the regulated feedback voltage. OTP1 indicates when die temperature has become excessive. OTP2 indicates when die temperature has become critical. Supertex inc ...

Page 13

... Supertex inc. CHL & Description CHH Shuts down the IC when supply voltage is too low. Turns OFF boost converter switch when instantaneous current becomes excessive. Operates cycle-by-cycle. The active channels remain ON, but with a lower V strings may not be lit ...

Page 14

... SFM2 Host Controller R Y1 XTAL Depending upon the crystal, a small loading capacitor may 1 be needed This schematic is a conceptual presentation and may not reflect actual implementation. Supertex inc. LED Drive Frequency f SYNC and 0. crystal Boost Frequency ...

Page 15

... Row #8 is out of sequence so that 9600Hz may be obtained without resistors (SFM pin = V 3. Hatched cells indicate illegal conditions. The PWM duty cycle may be erroneous but no damage to either the HV9957 nor LEDs will be in- curred. Supertex inc. SYNC Input 120Hz 180Hz 240Hz 250kΩ ...

Page 16

... High current, high frequency ground paths seperate from ground plane to avoid creating voltage differentials across ground plane Charge path (SW on) Discharge path (SW off) Pinout (top view) Supertex inc. (top layer) If sensitive circuitry adjacent to high voltage switching node, include a guard trace. To Host L BST GND ...

Page 17

... The exposed metal plate on the underside is at ground potential and may be connected to ground or left Plate floating. It provides heat sinking and should be soldered to a copper area on the PCB. Supertex inc. and a crystal connected, an internal crystal oscillator is used. DD 1235 Bordeaux Drive, Sunnyvale, CA 94089 ...

Page 18

... Drawings not to scale. Supertex Doc.#: DSPD-24QFNK74X4P050, Version A031609. (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to http://www.supertex.com/packaging.html.) does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such applications unless it receives Supertex inc. an adequate “ ...